RET191115
Invalid invoice number format
What the portal shows
Invoice number does not exist. Please enter a valid invoice number
The invoice number is missing, too long, or contains characters the rules do not permit.
What it means
An invoice number may be at most 16 characters and is restricted to letters, digits, hyphen and slash. Anything longer, blank, or containing other punctuation is rejected. Systems that build numbers by concatenating branch, year and sequence overrun the limit easily.
Common causes
- The number exceeds 16 characters — usually a concatenated branch/year/sequence.
- It contains spaces, hash, ampersand or other disallowed punctuation.
- The field is blank for some rows in the export.
- Excel stripped a leading zero or reformatted the value as a number.
How to fix it
- Check every flagged number is 16 characters or fewer.
- Restrict characters to letters, digits, hyphen and slash.
- Shorten your numbering scheme at source if it structurally overruns.
- Format the column as text before exporting so leading zeros survive.
This one is catchable before you upload
RET191115 is produced by something already present in your invoice data — our Invoice number format validation flags it before the file reaches the portal, so you fix it once instead of discovering it on upload day.
Related errors
Reviewed 13 August 2026. GSTN changes error wording and adds codes without notice, and this is general information rather than tax advice — confirm the current position on gst.gov.in or with your CA.