Save button in commcare web not working

I have imported an Xform survey.
I see the survey in CommCare, however, from there, I cannot save any further modifications.

I can modify things in the survey, but when I click on the SAVE button, nothing happens, and the SAVE button remains SAVE. It does not become SAVED. It's a dead button.
Why?

After Xform import I get the warning:

Warning

  • Form does not have a UIVersion attribute, one will be generated automatically