Separate conformance from acceptance
A validator tests the executed schema, business and profile rules. A recipient may also require an actual routing reference, purchase order, registered endpoint, permitted attachment or correct submission channel. Technical validity cannot confirm those agreements.
Keep the rejection evidence
Keep the portal’s exact message, submission time and the original file. Compare its required format/version with your report’s coverage. Ask the recipient to identify the missing requirement; do not change invoice amounts merely to silence an unclear portal message.
Check the new submission
After correcting the source, inspect the replacement, review changed findings and submit through the agreed channel. Peppol BIS file creation is separate from sending through a Peppol access point. Archive the final file and the recipient response yourself.