AtTally Sofper was established in the year 1999 by Mahesh Attal & Dinesh Attal at Visakhapatnam. Over the last 20 years, the company has grown from one office of 2 members to two offices of 25 members
Top 5 GSTR-1 and E-Invoice Errors in TallyPrime (And How to Fix Them)
It’s the 10th of the month. You hit submit on GSTR-1. The portal throws back a mismatch warning on Table 12. Somewhere in Vijayawada, your client’s accountant is calling about a rejected IRN too.
These aren’t rare glitches. GSTR-1 and e-invoice errors in TallyPrime follow the same five patterns, month after month, across most GST-registered businesses in Andhra Pradesh. Once you know the pattern, you can catch each one before it costs your client their Input Tax Credit — or you a late night.
This guide covers the five errors we see most at AtTally Sofper, why they happen, and the exact fix for each.
This is the most damaging error on the list. An invoice without a valid IRN and QR code isn’t a legal tax invoice under GST. Your buyer can’t claim ITC on it, even if the goods reached them fine.
Why it happens
Someone bills a sale in a hurry and forgets to generate the IRN before the truck leaves.
The business crossed ₹10 crore turnover and didn’t realise a new 30-day reporting window applies.
Since 1 April 2025, any business with Aggregate Annual Turnover (AATO) of ₹10 crore or more must report each invoice to the Invoice Registration Portal (IRP) within 30 days of the invoice date. Miss that window, and the IRP won’t issue an IRN at all — there’s no way to reopen it.
The fix
In TallyPrime, set e-Invoicing Applicable to Yes under F11, so every sales voucher prompts for IRN generation on save.
If you’re over ₹10 crore turnover, run a weekly report of invoices older than 20 days with no IRN. Clear the backlog before day 30.
If a document already crossed 30 days, you can’t get an IRN. Talk to your tax practitioner about a credit note and re-invoicing instead.
GSTN now cross-checks the values you enter in Table 12 (HSN Summary) against your other GSTR-1 tables — B2B invoices, B2C invoices, exports, amendments, and credit notes. If the totals don’t line up, the portal flags it.
Why it happens
An export or B2C sale gets entered under the wrong tab in Table 12 — B2B instead of B2C, or the reverse.
A rate-wise value in Table 12 drifts from the totals in Tables 4, 6, 7, 8, or 9 by a small margin that adds up.
Right now, this check runs in warning mode. You can still file with a mismatch flagged. That’s changing — the direction of GSTN’s rollout is toward blocking submission once the gap crosses a threshold, so it’s worth fixing this habit now, not later.
The fix
In TallyPrime, go to GSTR-1 > HSN Summary – 12, then press Alt+R (Reset Summary) to regenerate it from your current voucher data.
Check that every B2B invoice sits in the B2B tab of Table 12, and every B2C invoice sits in the B2C tab. Exports usually belong under the B2C tab unless the buyer is GST-registered.
Download the GSTR-1 summary PDF from the portal and compare table totals before you file, not after.
3. Trying to Edit an IRN-Linked Invoice Directly
Once an invoice has an IRN, some fields lock. You can’t change the invoice number or the IRN itself inside GSTR-1. Trying anyway causes a rejection or a silent data mismatch that surfaces weeks later.
Why it happens
A team member spots a wrong buyer GSTIN or tax rate after the IRN is generated and edits the invoice directly in Tally, without touching the IRP record.
Only part of an invoice gets corrected — say, the taxable value, but not the matching tax amount — which creates a new mismatch instead of fixing the old one.
The fix
Still inside the cancellation window (commonly 24 hours from IRN generation)? Cancel the IRN on the IRP and raise a fresh, correct invoice.
Window closed? Use a credit note or debit note to adjust the value, and report that separately in GSTR-1. Don’t try to alter the original invoice.
For genuine GSTR-1 corrections after filing — like a wrong buyer GSTIN — use the amendment tables (9A for B2B amendments), not a direct edit.
4. Invoice Reported in the Wrong GSTR-1 Period
An invoice dated 28th of one month but reported in the next month’s GSTR-1 creates a timing mismatch. Your buyer may try to claim ITC in the earlier period, based on the IRP registration date, while your return shows it in the later one.
Why it happens
A sale gets billed late, close to the return filing deadline, and slips into the following month’s data.
For e-invoiced transactions, the invoice date must match the IRP registration date. A big gap between the two gets rejected by the IRP outright.
The fix
Reconcile your IRN register against your sales register every week, not just at month-end. Catch date gaps early.
If the error already made it into a filed return, use Table 9A to amend the invoice date. This falls under the general amendment window, open up to the following September.
Set a hard internal rule: no invoice gets billed without an IRN generated the same day, if your turnover requires one.
5. Wrong HSN Code Length for Your Turnover
GST requires a 4-digit HSN code below ₹5 crore turnover, and a 6-digit code above it. Use the wrong length, and the portal rejects the entry — or worse, accepts it and creates a mismatch with your e-invoice data later.
Why it happens
A business crosses ₹5 crore turnover mid-year and keeps using the old 4-digit codes out of habit.
Manual HSN entry introduces typos — GSTN has removed free-text HSN entry, so this now shows up as a dropdown selection error instead.
The fix
In TallyPrime, confirm your HSN/SAC length is set correctly under company GST features, based on your current turnover slab.
If an HSN code shows as invalid, validate it against your e-invoice or e-way bill portal credentials directly inside TallyPrime.
Only B2B sales but no B2C, or the reverse? Add a nominal ₹1 nil-rated entry in the missing tab of Table 12 as a workaround, until the GSTN portal handles single-category filers better.
Quick Comparison: All Five Errors
Error
Where It Shows Up
Fastest Fix
Missing or late IRN
IRP rejects invoice; buyer’s ITC blocked
Generate IRN same-day; track the 30-day window
HSN Table 12 mismatch
GSTR-1 filing warning
Reset HSN summary; check B2B vs B2C tabs
Editing an IRN-linked invoice
Rejection or silent data mismatch
Cancel and reissue, or use a credit note
Wrong filing period
Buyer ITC timing mismatch
Weekly reconciliation; Table 9A amendment
Wrong HSN code length
Entry rejected or later mismatch
Match HSN length to current turnover slab
Running an audit trail across all five takes time most accountants don’t have during filing week. For a broader look at how TallyPrime data can support review and sign-off, see our guide on TallyPrime for CAs, from bookkeeping to strategic growth.
Catching one of these errors right now?
AtTally Sofper can check your TallyPrime GST setup remotely and fix what’s causing the mismatch, before your next filing deadline.
Usually a timing or category gap. An invoice may have its IRN cancelled in the IRP but not in your books, or it may fall in one return period while the IRP registered it in another. Start by comparing your IRN register to your sales register, not the filed return PDF.
Can I edit an invoice after the IRN is generated?
Not the invoice number or IRN itself. You can still change some fields like invoice date, value, or customer details, but consistently — changing one figure without the matching one causes a fresh mismatch.
What happens if I miss the 30-day e-invoice reporting window?
If your turnover is ₹10 crore or more, the IRP will refuse to generate an IRN for that document at all. There’s no official way to reopen the window, so the invoice stays legally invalid under GST.
How do I fix an HSN mismatch in GSTR-1 Table 12?
In TallyPrime, reset the HSN summary under GSTR-1 to pull fresh data from your vouchers. Then check that B2B and B2C entries sit in their correct tabs, since Table 12 now validates against your other GSTR-1 tables.
Why does TallyPrime show an HSN summary error while filing GSTR-1?
Often it’s a configuration issue — your HSN/SAC Summary setting under F11 may be set to exclude B2C sales, or your HSN code length may not match your turnover slab. Correcting the F11 setting and resaving the summary usually clears it.
What’s the correct HSN code length for my business?
4 digits if your turnover is below ₹5 crore, 6 digits if it’s ₹5 crore or above. Using the wrong length gets flagged either at entry or during Table 12 validation.
Can I still file GSTR-1 if there’s a Table 12 mismatch warning?
For now, yes — the validation runs in warning mode, so you can file despite the alert. That’s expected to tighten over time, so it’s safer to fix the mismatch than to rely on the warning staying soft.
How do I correct a GSTR-1 invoice date error after filing?
Use Table 9A to amend a B2B invoice date. Enter the original details first, then the corrected ones in the amendment section. This falls under the general amendment window, open until the following September’s filing.
Does my TSS subscription affect e-invoice and GSTR-1 accuracy?
Yes. TSS keeps TallyPrime connected to the IRP and GST systems for real-time validation. If it lapses, e-invoice generation and GST error checks stop working, even though offline billing continues. See our guide on renewing Tally TSS for the renewal steps.
Who should I contact if these errors keep recurring in my GSTR-1?
If the same mismatch shows up month after month, it’s usually a TallyPrime configuration issue rather than a one-off data entry mistake. A remote setup check, like the one AtTally Sofper offers, usually finds the root cause faster than fixing each return manually.
AtTally Sofper: Local Help With GST Filing Errors in TallyPrime
We’re AtTally Sofper Pvt. Ltd., an authorized Tally partner with offices in Visakhapatnam (Vizag) and Vijayawada.
For GSTR-1 and e-invoice errors, we help with:
Diagnosing recurring Table 12 and HSN mismatches at the TallyPrime configuration level
Setting up IRN generation so the 30-day window never becomes a last-minute scramble
Fixing amendment and correction workflows for CAs managing multiple client GSTINs
TSS renewal, so your compliance checks never quietly stop working mid-filing
We offer online and remote support, so most fixes don’t need an office visit. If your GSTR-1 keeps throwing the same error every month, reach out to our team. We’ll check your setup and fix what’s causing it.
Top 5 GSTR-1 and E-Invoice Errors in TallyPrime (And How to Fix Them)
It’s the 10th of the month. You hit submit on GSTR-1. The portal throws back a mismatch warning on Table 12. Somewhere in Vijayawada, your client’s accountant is calling about a rejected IRN too.
These aren’t rare glitches. GSTR-1 and e-invoice errors in TallyPrime follow the same five patterns, month after month, across most GST-registered businesses in Andhra Pradesh. Once you know the pattern, you can catch each one before it costs your client their Input Tax Credit — or you a late night.
This guide covers the five errors we see most at AtTally Sofper, why they happen, and the exact fix for each.
1. Missing or Late IRN Before Dispatch
This is the most damaging error on the list. An invoice without a valid IRN and QR code isn’t a legal tax invoice under GST. Your buyer can’t claim ITC on it, even if the goods reached them fine.
Why it happens
Since 1 April 2025, any business with Aggregate Annual Turnover (AATO) of ₹10 crore or more must report each invoice to the Invoice Registration Portal (IRP) within 30 days of the invoice date. Miss that window, and the IRP won’t issue an IRN at all — there’s no way to reopen it.
The fix
For a full setup walkthrough, our guide on e-way bill and e-invoicing setup in TallyPrime for Andhra Pradesh covers this step by step.
2. HSN Table 12 Value Mismatch
GSTN now cross-checks the values you enter in Table 12 (HSN Summary) against your other GSTR-1 tables — B2B invoices, B2C invoices, exports, amendments, and credit notes. If the totals don’t line up, the portal flags it.
Why it happens
Right now, this check runs in warning mode. You can still file with a mismatch flagged. That’s changing — the direction of GSTN’s rollout is toward blocking submission once the gap crosses a threshold, so it’s worth fixing this habit now, not later.
The fix
3. Trying to Edit an IRN-Linked Invoice Directly
Once an invoice has an IRN, some fields lock. You can’t change the invoice number or the IRN itself inside GSTR-1. Trying anyway causes a rejection or a silent data mismatch that surfaces weeks later.
Why it happens
The fix
4. Invoice Reported in the Wrong GSTR-1 Period
An invoice dated 28th of one month but reported in the next month’s GSTR-1 creates a timing mismatch. Your buyer may try to claim ITC in the earlier period, based on the IRP registration date, while your return shows it in the later one.
Why it happens
The fix
5. Wrong HSN Code Length for Your Turnover
GST requires a 4-digit HSN code below ₹5 crore turnover, and a 6-digit code above it. Use the wrong length, and the portal rejects the entry — or worse, accepts it and creates a mismatch with your e-invoice data later.
Why it happens
The fix
Quick Comparison: All Five Errors
Running an audit trail across all five takes time most accountants don’t have during filing week. For a broader look at how TallyPrime data can support review and sign-off, see our guide on TallyPrime for CAs, from bookkeeping to strategic growth.
AtTally Sofper can check your TallyPrime GST setup remotely and fix what’s causing the mismatch, before your next filing deadline.
Talk to Our Team
Frequently Asked Questions
Why is my GSTR-1 not matching my e-invoice data?
Usually a timing or category gap. An invoice may have its IRN cancelled in the IRP but not in your books, or it may fall in one return period while the IRP registered it in another. Start by comparing your IRN register to your sales register, not the filed return PDF.
Can I edit an invoice after the IRN is generated?
Not the invoice number or IRN itself. You can still change some fields like invoice date, value, or customer details, but consistently — changing one figure without the matching one causes a fresh mismatch.
What happens if I miss the 30-day e-invoice reporting window?
If your turnover is ₹10 crore or more, the IRP will refuse to generate an IRN for that document at all. There’s no official way to reopen the window, so the invoice stays legally invalid under GST.
How do I fix an HSN mismatch in GSTR-1 Table 12?
In TallyPrime, reset the HSN summary under GSTR-1 to pull fresh data from your vouchers. Then check that B2B and B2C entries sit in their correct tabs, since Table 12 now validates against your other GSTR-1 tables.
Why does TallyPrime show an HSN summary error while filing GSTR-1?
Often it’s a configuration issue — your HSN/SAC Summary setting under F11 may be set to exclude B2C sales, or your HSN code length may not match your turnover slab. Correcting the F11 setting and resaving the summary usually clears it.
What’s the correct HSN code length for my business?
4 digits if your turnover is below ₹5 crore, 6 digits if it’s ₹5 crore or above. Using the wrong length gets flagged either at entry or during Table 12 validation.
Can I still file GSTR-1 if there’s a Table 12 mismatch warning?
For now, yes — the validation runs in warning mode, so you can file despite the alert. That’s expected to tighten over time, so it’s safer to fix the mismatch than to rely on the warning staying soft.
How do I correct a GSTR-1 invoice date error after filing?
Use Table 9A to amend a B2B invoice date. Enter the original details first, then the corrected ones in the amendment section. This falls under the general amendment window, open until the following September’s filing.
Does my TSS subscription affect e-invoice and GSTR-1 accuracy?
Yes. TSS keeps TallyPrime connected to the IRP and GST systems for real-time validation. If it lapses, e-invoice generation and GST error checks stop working, even though offline billing continues. See our guide on renewing Tally TSS for the renewal steps.
Who should I contact if these errors keep recurring in my GSTR-1?
If the same mismatch shows up month after month, it’s usually a TallyPrime configuration issue rather than a one-off data entry mistake. A remote setup check, like the one AtTally Sofper offers, usually finds the root cause faster than fixing each return manually.
AtTally Sofper: Local Help With GST Filing Errors in TallyPrime
We’re AtTally Sofper Pvt. Ltd., an authorized Tally partner with offices in Visakhapatnam (Vizag) and Vijayawada.
For GSTR-1 and e-invoice errors, we help with:
We offer online and remote support, so most fixes don’t need an office visit. If your GSTR-1 keeps throwing the same error every month, reach out to our team. We’ll check your setup and fix what’s causing it.
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