Can't install app by downloading from Thunkable email link

I haven’t seen anything about this recently on the forums. When I click the Download button, it generates an email message from Thunkable Support after about an hour. I click on the CLICK HERE TO DOWNLOAD button and then the Download button on the next screen but nothing else happens.

The instructions in the email message say to go to Settings–>General–>Device Management but on my iPhone 11 running iOS 13.6, there is no entry for Device Management in General. Do I need to install a profile? How can I get this to work?

I had to erase and restore my iPhone and for whatever reason, that fixed this problem. Yay!

And… now it’s back. I click the Download button and it changes from light blue to dark blue but nothing else happens.

Anyone else having problems installing downloaded iOS apps?

I tried this in Chrome and Safari.