We can not select Sponsor (staff member setup as an approver) for approval at the final approval stage for a project

There could be a few reasons why the staff member is not showing to select:

1. Check to ensure that a staff member has been given the position for approval and is linked to the project team object. For example if you have setup that the Sponsor can approve the sign off, then ensure that there is a staff member with this position linked to the project. 

2. Please check to ensure that the staff member who is added to the Project Team with the correct project position (linked in the workflow who can approve the sign off) has been linked correctly to the User login. 

You cannot assigned staff members to approve projects unless they are linked to a user login. 

1. Check to ensure that the position that you have select to be able to do the approval has the appropriate permissions set (CAN SIGN OFF - SIGN OFF) within the project settings > project position section:

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