Why is my bill not synced to Microsoft Dynamics NAV even though an active vendor exists in NAV?

Cause: 

The problem arises because another vendor with the same name is marked as blocked in Microsoft Dynamics NAV (MSNAV).

For example, when attempting to sync the bill with vendor name "S000000805", MS NAV mistakenly identifies it as "S000000105", the blocked vendor, due to the identical names. MS NAV checks vendors by name and assigns the first match, which is the blocked vendor. If no action is taken, after three more retries, an error will appear in the UI: 
Request failed with status code 400: [Application_DialogException] You cannot create this type of document when Vendor S000000105 is blocked with type All.

Resolution:

To resolve this issue, follow these steps:

1. Edit the Vendor Name in MSNAV: In MSNAV, edit the name of the blocked vendor to differentiate it from the active vendor. You can add a suffix like "[depreciated]" or "[blocked]" to the name of the blocked vendor to distinguish it from the active one.

2. Resync the Bill: After editing the vendor name in MSNAV, attempt to resync the bill with the active vendor. Then verify that the bill now syncs correctly to MSNAV without any issues.