I will be the first to admit, that I find it exciting every time a new update of the Operating System on Mac is released, or for my iPhone. But, I have also learned the hard way that sometimes it is better to wait a little bit. Even though the software has been tested at multiple clients with a vast amount of different setups, then there will still be bugs that might or might not affect you. Previously I have updated too fast on both my Mac and my iPhone, and now I slowly started to learn.
I, therefore, did not upgrade to iOS 15 when it came out, but I waited until iOS 15.0.1 and hope that some of the worst bugs would have been corrected. As you can probably see I am very proud of myself here ;-)
Still, after upgrading to iOS 15.0.1, I have started experiencing a very very annoying bug.
The bug is related to my Exchange Account, which is basically my work email. Besides the work-related Exchange account, I also have a few Gmails and iCloud, and the problem only occurs at the Exchange account.
Every now and then, I will get the error message you see in the picture. "Password Incorrect". I will then enter the password, which is accepted and my email will then work for a few hours, or a day, there is no clear pattern. In that period I will be able to read and send emails until it suddenly decides to change my password, or whatever is going on.
The bug is quite annoying as, when the error message is there, it stops everything else I am doing. If I click "cancel", it will pop up half a second later, basically making it very difficult and time-consuming for me to open the 1Password app where I store the password.
With a quick Google search, I can see that I am not the only person experiencing the problem, which actually goes back to iOS 15 => https://discussions.apple.com/thread/253174374
If you do not have a real need to upgrade now, I would encourage you to wait until the bug has been squeezed. I did not experience it at iOS 14.