Mutabiq reports MTB-XSD-00 when the schema engine itself failed to run on the document, so the UBL 2.1 schema check has no result. Its severity is Error, not a pass: a report whose schema check did not run must never be read as a document that passed, by a person or by a pipeline.
Recorded in Mutabiq's decisions log under “2026-09-27 — MTB-XSD-00 is an ERROR: a report whose schema check did not run is not PASS”.
Five checks a month on the Free plan. The file is checked in memory and is never stored.
What Mutabiq reports
One entry for each way this rule can be reported.
Reported as
What kind of value was found — empty, not_15_digits and the like — never the value itself.
Schema check could not run
Reported asengine_errorthe check could not run
What is wrong
Mutabiq could not run the UBL 2.1 schema check on this document. The check itself did not complete, so this report is incomplete. Nothing was found in your invoice here; the other checks in the report ran normally.
What to check in your ERP
Nothing in your ERP caused this and nothing there needs changing. Upload the same file again. If the message keeps appearing for the same document, send it to support so the schema check can be looked at.