First of all, please clear out any other fields on the detail line of the transaction, such as Analysis Code, Cost Centre etc and then clear out the Project Code field too. Then once all the fields are blank, repopulate them one by one. The fields can depend on one another and if one field has been changed in some way, then this can cause an issue.
Once they have all been cleared and repopulated, the error should no longer appear.
If the above does not resolve this, then it may be that the project has been set up directly in Dimensions instead of through FocalPoint.
When using projects with Dimensions and FocalPoint (and standard functionality only), projects have to be set up through FocalPoint's "Project Commencement" screen or else this error will appear. It is due to the project only existing in the Dimensions tables and not the FocalPoint ones.
If you have custom functionality to create your project records, such a a Workflow Form or integration with another piece of software, then this may differ.
In order to resolve the issue, please log a new case online and reference this article. If you need assistance logging your case
Error - 'Invalid Project' when selecting a project on an expense that definitely exists in Dimensions
Updated over a week ago