Mobile testing troubleshooting for "Invalid Name!" error pop up

Would anyone be able to help me with a problem I am having?

I am trying to automate a test case for a mobile app. I am getting stuck on this error pop up while attempting to TAP the “Let’s Go” button on the emulator on the right.

Error pop up:

Please provide any tips or advice you may have to override this error. I am not very technically adept and am just trying to get past this screen!