00103: Signature has no time reference
What it means
SdI code 00103 means the electronic signature on the file has no time reference.
The usual cause
Check whether your signing software included a time reference in the signature.
How to fix it
Sign the file again with software that adds a time reference, and send it under a new name.
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.