00300: Sender's tax number not valid
What it means
SdI code 00300 means the tax number of the sender, in IdTrasmittente (1.1.1.2 IdCodice), is not valid.
The usual cause
For an Italian sender SdI checks the code in the tax register, so a typo or a code that does not exist fails. Codes issued by a foreign authority are not checked.
How to fix it
Correct IdCodice in the transmission data to the sender's exact codice fiscale and send the file again.
Elements the check reads
-
1.1.1.2 IdCodice
The code as published
Read the official document . Source: Elenco dei controlli effettuati sul file fattura del Sistema di Interscambio, version 2.0, published by Agenzia delle Entrate, fatturapa.gov.it, read on 8 November 2026.
Klarbon explains each code in its own words; the official wording is in the document linked above.
Look at your file
Open the invoice in your browser to find the fields this code names: Open an Italian FatturaPA invoice. Open an Italian FatturaPA invoice
Other SdI codes
- 00301 Seller's VAT number not valid
- 00302 Seller's tax number not valid
- 00303 Tax representative's VAT number not valid
- 00304 Tax representative's tax number not valid
- 00305 Buyer's VAT number not valid
- 00306 Buyer's tax number not valid
- 00311 Recipient code not valid
- 00312 Recipient code not active
- 00320 Seller's VAT number and tax number do not match
- 00321 Seller's tax number is not in the VAT group
- 00322 Tax number missing with a VAT group number
- 00323 Seller's VAT number closed more than five years ago
- 00324 Buyer's VAT number and tax number do not match
- 00398 Central office code used where a specific office exists
- 00399 Private-sector format used for a public body