What “rejected” means exactly
When you transmit a document, the tax authority replies with a message that is either acceptance or rejection. That message is the validation: until it arrives, the document is not firm. If it arrives as a rejection, the document does not exist for tax purposes. It does not support your sale, it does not support your customer's expense, and it generates input VAT for nobody.
The real causes, in order of frequency
The version 4.4 technical annex defines dozens of validations that end in rejection. Almost all of them fall into six groups:
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The customer's identification does not exist or is mistyped
The tax authority checks that the number is real and in its registers, and that it respects the format for its type: an individual's number is nine digits, no hyphens and no leading zero; a company's is ten characters. One hyphen too many and the document falls.
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The key or the sequence number is badly built
Two numbers with a fixed structure. If the sequence skips, repeats, or does not match the document type and point of sale it declares, the rejection is automatic.
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There is a zero where there should be a number
Quantity and unit price must be greater than zero. And where the tax does not apply you write “0” — you do not leave the field empty: absent and zero are not the same thing to the tax authority.
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The totals do not match the lines
The tax authority redoes the arithmetic. It adds the lines, recalculates the tax and compares the payment methods against the total. One cent of difference from a bad rounding and it rejects.
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An exemption that does not match the real authorisation
When you invoice exempt, the tax authority goes looking for the authorisation: it checks the number, the issue date and the percentage. If the percentage applied is higher than the one authorised, or the authorisation has expired, it rejects.
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The CABYS code does not fit the VAT treatment you gave it
The product code determines the rate. If CABYS says the item is taxable and the line goes exempt, or the other way round, the tax authority sees it. How CABYS decides the rate.
What to do once it has happened
Fix the cause, issue a new document with the next sequence number, and state in the reference section which document it is replacing. That new document goes to the customer by the agreed means.
What you must not do is issue a credit note. The regulation says so without hedging: when the tax authority's message is a rejection, for tax purposes the corresponding credit note must not be made. Issuing one anyway creates a document that voids something that never existed, and that genuinely does disorder your accounts.
- Rejected
- The tax authority's message · the document is worthless
- Fix
- The specific cause · identification, amount, CABYS…
- Issue another
- Next number, referencing the previous one
The only thing that really works: not getting there
All of these checks can be made before transmitting, because they are known, written rules. The difference between one system and another is not what it does after a rejection — there is not much left to do — but how many rejections it avoids.
The warning comes before, not after
While you are filling the document in, it is checked against the version 4.4 rules. If something is missing, you are told before it goes to the tax authority.
See how it worksAbout this article. The rejection rule is in articles 10 and 19 of the Electronic Documents Regulation; the specific validations, in the version 4.4 structures annex (resolution MH-DGT-RES-0027-2024 and its updates).
Verified as of 24 September 2026. Tax rules change. This is information, not tax advice.
Sources: Ministry of Finance Current legal texts (Sinalevi)