SDI-00400:XML schema validation failure
FatturaPA XML must conform exactly to the official XSD schema published by Agenzia delle Entrate. Any structural deviation causes rejection.
Engine Classification
Financial or legal field · Modification blocked by policy
Reason: FatturaPA XML must conform to the official XSD schema from Agenzia delle Entrate. Schema violations indicate structural issues in how your ERP/invoicing system generates XML. Contact your software vendor or update your invoice generation template to match the current FatturaPA specification.
What is SDI-00400?
SDI-00400 is a fatal validation rule defined in the FatturaPA specification (ITA national rules). It checks whether xml schema validation failure.
When this rule fires, the invoice is non-compliant and will be rejected by Peppol access points and national validation services. The sending system receives a rejection response and the invoice does not reach the buyer.
Why This Error Matters
SDI-00400 is a hard failure. Invoices that trigger this rule are rejected at the access point and never reach the recipient. In Peppol networks, this means your sending system receives an MLR (Message Level Response) with a rejection status. The invoice must be corrected and re-sent, adding delay to your payment cycle.
Validator Behavior
- ·Causes invoice rejection
- ·Rejected by SDI (Sistema di Interscambio)
- ·Error returned: SDI-00400
- ·Specification: FatturaPA
How to Fix It
Technical Reference
Common Causes
- ·Custom fields causing schema violation
- ·Invalid XML characters
- ·Wrong element order or nesting
Seeing this in production? The API handles SDI-00400 automatically. See the fix response →
Frequently Asked Questions
FatturaPA XML must conform exactly to the official XSD schema published by Agenzia delle Entrate. Any structural deviation causes rejection.
Validate the XML structure against the FatturaPA schema before submission. You can also use Invoice Navigator's automatic Fixer tool to correct this instantly.
Yes, SDI-00400 is a critical error that will cause invoice rejection. It must be fixed before submission to ensure your invoice is accepted by the recipient's system.
Many instances of SDI-00400 can be automatically corrected using Invoice Navigator's Fixer tool. Upload your invoice and the tool will identify and fix common issues, including xml schema validation failure.
Last updated: 19 January 2026
Handle SDI-00400 Automatically in Your Pipeline
The compliance engine auto-remediates this error with controlled safety policies and evidence pack generation.