HS-1090 | Step2 not possible | could not test model

Hello to all.
I am studying HST to create new workflows.

Currently I wanted to redo HS-1090 as tutorial. However, everything runs fine till end of described step1. Adding Lookup, and setting csv was successful, but now I could not run Test Model since the Button "Next" deactivated and "gray".

Do you have teh same issue?

Thanks.

Alex