This occurs when there is corruption of the database. Please check:
Open from Transaction, Vendor's Invoice.
The Invoice has missing information in the Vendor. Please update it and save.
You may need to delete the transaction and create it again if the vendor payment is still unable to detect the invoices
If the invoice is missing from Transaction, Vendor's Invoice, but it is available in Housekeeping, Administrative Tools, Database Viewer, you need to delete the Invoice from Database Viewer.
Look for the table Sbill and SbillL and click edit.
To delete that entry, mark it 'black' at the 1st empty column on the left.
Click on 'X' to exit and click the Exit button.
Open from Transaction, Vendor's Invoice, and create the transaction again for the Vendor's invoice.