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. This error involves a protected field — Invoice Navigator flags it in your pipeline so your team can correct it at the source.
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.
SDI-00400 involves a financial or legal field that cannot be auto-modified by policy. Invoice Navigator detects and flags this error immediately, but the correction must be made manually in your ERP or invoicing software.
Related Content
Last updated: 3 March 2026
Detect SDI-00400 Before Submission
This error involves a financial or legal field that cannot be auto-modified. The compliance engine flags it immediately with a clear diagnosis so your team can fix it at the source.