You must use this server:
https://iosbuildservertest.appinventor.mit.edu/
and you also need an Apple Developer account.
See also here: Problem build ipa - #2 by Anke
You must use this server:
https://iosbuildservertest.appinventor.mit.edu/
and you also need an Apple Developer account.
See also here: Problem build ipa - #2 by Anke