Error Messages for Developer

I am listed as the main developer on an application. I created a function and get the following error when I execute the function from the create function screen. At this point I'm not concerned about the actual error but that as a developer I can't see the error message. Now I either need to contact the owner and walk them through the steps to recreate the error or I need the owners credentials to see the error myself. The first is time consuming because the owner is not a programmer. The second is a security problem.

Execution Failed Error occured please contact application owner.