A blocked IRN doesn’t just delay one invoice — it means that invoice is legally invalid under GST until it’s resolved, and your buyer can’t claim input tax credit on it in the meantime.
E-invoicing is mandatory for businesses with aggregate turnover above ₹5 crore in any year since FY 2017-18, calculated at the PAN level across all GSTINs. Businesses above ₹10 crore must also report invoices to the IRP within 30 days of the invoice date, or the IRN gets rejected outright.
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The Errors That Come Up Most Often
HSN code mismatches. From FY 2025-26, CBIC has been enforcing 6-digit HSN accuracy for businesses above ₹5 crore turnover (4-digit minimum below that). A 4-digit code where 6 digits are required is a frequent, easily missed rejection cause.
The 30-day reporting window, missed. If your turnover is ₹10 crore or above, an invoice dated more than 30 days ago simply won’t generate an IRN — the IRP rejects it outright, no exceptions, no late submission path. This catches businesses doing month-end batch corrections or backdating credit notes without realizing the window has already closed.
Multi-outlet turnover blindness. Aggregate turnover is calculated per PAN, not per GSTIN or per outlet. A retail or restaurant chain with several locations, each individually under ₹5 crore, can collectively cross the threshold without anyone connecting the totals — and then every outlet is non-compliant simultaneously the moment someone notices.
Inconsistent product masters across billing systems. If different outlets or branches use different software, or the same software configured inconsistently, HSN codes and tax rates can vary for what should be the identical product — creating IRN validation failures that look random but trace back to a master-data problem.
MFA/2FA session failures. Since April 2025, multi-factor authentication is mandatory for GST portal access, including e-invoice generation. A session that hasn’t completed 2FA properly fails silently in some billing software integrations, producing what looks like an IRN generation error but is actually an authentication issue.
What to Check, in Order
- Confirm your invoice date is within the 30-day window if your turnover is ₹10 crore or above — this is the single fastest thing to rule out.
- Verify the HSN code length matches your turnover-based requirement (6 digits above ₹5 crore).
- If you operate multiple outlets, calculate your actual combined PAN-level turnover for the current and prior years — don’t assume any single outlet’s figure represents your obligation.
- Confirm 2FA/MFA is completing properly in your billing software’s GST portal connection, not just assumed to be working.
What Happens If an Invoice Stays Unresolved
An invoice without a valid IRN is treated as invalid under GST law — not just delayed, invalid. Your buyer cannot claim ITC on it, which means unresolved IRN errors don’t just create an internal headache, they actively damage your relationship with the client waiting on that invoice.
The Retail Chain Problem, Specifically
Multi-location businesses deserve a closer look here because the failure mode is different from a single-location business. A restaurant group with four outlets might individually show ₹1.3 crore each — comfortably under any single GSTIN’s radar — while the combined PAN-level turnover crosses ₹5 crore without a single manager or franchise owner realizing it. The compliance obligation begins the moment the combined threshold is crossed, not the moment someone in finance notices. If you operate more than one location under the same PAN, calculating your actual combined turnover — not your highest individual outlet’s figure — is the first thing worth doing before assuming you’re exempt.
Common GST E-Invoice Error Codes
2150 – Duplicate IRN Request
Occurs when the same invoice number has already been reported to the IRP. Verify whether an IRN already exists before attempting regeneration.
2172 – Invalid HSN Code
Usually triggered when the HSN code does not match the current GST schema requirements or master data.
2182 – Invoice Date Exceeds Allowed Reporting Period
Common for businesses above the prescribed turnover threshold when the invoice is reported beyond the permitted timeline.
3028 – GSTIN Validation Failure
Occurs when supplier or recipient GSTIN details are incorrect, inactive, or cancelled.
Authentication / MFA Errors
Often caused by expired API credentials, incomplete MFA setup, or GST portal authentication issues.
Frequently Asked Questions
Can I cancel and regenerate an IRN if I made an error?
Yes, but only within 24 hours of generation. After that window, cancellation isn’t available — you’d need to issue a credit note and report that separately, rather than undo the original IRN.
Does e-invoicing apply to B2C transactions?
No, the e-invoicing mandate applies to B2B transactions, exports, and supplies to government entities — B2C invoices, nil-rated supplies, and supplies to exempt persons fall outside it regardless of turnover.
If my turnover dropped below ₹5 crore this year, am I exempt now?
No — once your turnover has exceeded ₹5 crore in any financial year since FY 2017-18, the e-invoicing requirement continues even if a later year’s turnover falls back below the threshold.
Are credit notes and debit notes covered by the same IRN requirement?
Yes — many businesses generate IRNs correctly for sales invoices but forget that credit and debit notes against qualifying B2B invoices also require IRN, which is itself a common source of compliance gaps.
References
- GSTN e-invoicing schema documentation (Invoice Registration Portal)
⚠️ E-invoicing thresholds have been lowered multiple times since 2020 and may change again — confirm the current applicable threshold at the official GST e-invoice portal before relying on this figure for your business.
Last Updated: 22 June 2026
Reviewed By: TaxKitab Direct Tax Team
If your e-invoicing errors are turning up because your monthly filings don’t reconcile cleanly, that’s the same underlying gap covered in our post on ITC mismatches between GSTR-2B and books — worth a look if reconciliation generally feels like a recurring fire drill.Call or WhatsApp: +91 7448200422Email: info@taxkitab.comWebsite: taxkitab.comSee our GST Return Filing service, or visit Contact.
