Same exact question. The only thing I can think of is that I had created a user before with that email address and added it to the Sandbox test users. I then deleted that user, but now I can't add that user back. However, I cant find anywhere within App Store Connect for traces of that user so it's super annoying.

Same issues.

I don't understand why this is marked as Solved. Clearly many people still have this issue and there has been no 'fix' per se, simply some workarounds. Big Sur on MBP 2016, after the MBP goes to sleep and wakes up the wifi is disconnected, the only way to get it back up is to turn the wifi off and back on. very annoying. have tried all the 'fixes' suggested - resetting NVRAM, renaming location, setting dns to 8.8.4.4. DHCP and HOST etc. Nothing seems to work.

Big Sur on MBP 2016, after the MBP goes to sleep and wakes up the wifi is disconnected, the only way to get it back up is to turn the wifi off and back on. very annoying. have tried all the 'fixes' suggested - resetting NVRAM, renaming location, setting dns to 8.8.4.4. DHCP and HOST etc. Nothing seems to work.