User is creating a vendor bill, but the project that needs to be linked is not appearing in the drop-down of the Create Vendor Bill screen.
This issue can occur because of two reasons. It could be because of project assignments in place. If you have employees assigned to a project, but not vendors, you will be unable to see the project when creating the vendor bill. You must assign the relevant vendors to the project to ensure you can create the vendor bills for it. Check CORE Help Center for details.
The project you want to choose might be set as Inactive. In this case, you can set the project to Active. Check CORE Help Center for details.