Greetings,
We have a strange problem with our users happening in the morning on their mobile devices (Samsung Galaxy, Ipads, etc.): event if the password is stored on the device it's being asked again and after entering the correct one it keeps saying that it's incorrect. I found that restarting the IIS service on the Exchange server seems to resolve the issue and everything starts to work again until the next morning.
Do you have any idea on what could be causing the problem or where I can start investigating?