Document number already in use while saving changes under the Company Settings. This message can come up for any of the document types in use.

The reason is that a document number has already been used/processed but is appearing as the next document number in the sequence on Company Settings.

This can apply to any of the different document types that are in use. The message pop-up will show which document type number needs to be edited.

For this example, we will use Supplier Payments

The below message will appear when making a change on Company Settings or when saving Company Settings. 

1. You need to verify what was the last document number that was used under the Supplier Payment. Navigate to Suppliers > Transactions > Supplier Payments
   
   
   
   
2. Make sure that the next document under the Company Settings > Documents and Statements > Document Numbers > New Document Number has not been used previously. Change the next document to the next number in the sequence.

Click on Save once the change has been made.