The thing somehow got a three letter password which is unrelated to anything. I went to settings and input an app specific password but it still periodically pops up with the same three dots asking for a new password. Reentering the password allows the dialog to go away (and I get some incoming email) but the thing reverts soon after
Reentering the password allows the dialog to go away (and I get some incoming email) but the thing reverts soon after.
The latest eM Client V10.4.5608 on Mac for me personally after updating also caused an invalid app password and wouldn’t accept the previous app password. Unknown why that happened.
So I went into the Apple Account and “removed and regenerated a new app password” for the desktop and it’s been fine ever since. So suggest you do that and see if it fixes that for you.