This error message appears in the Sync details panel when a supplier cannot be synced to your ERP because its email address fails validation. The supplier is not synced, and the Suppliers row shows Failed.
Cause
The email address on the supplier record is missing or not in a valid format, so the ERP rejects the record.
Solution
Open the Sync details panel and note the affected suppliers (supplier name, tax number, external ID).
Use the Go to [ERP] link to open the supplier or vendor record in your accounting system.
Correct the email address so it is valid.
Return to Payhawk and run the sync again.