Hello, finally the problem is resolved for me.
I tried but with no success the following:
1. search credentials manager in start.
2. click windows credentials.
3. Delete all the credentials from there.
4. relaunch outlook, enter password and check the box remember password and see if that helps?
If that does not help try creating this registy key -
HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Outlook\AutoDiscover
New Dword - ExcludeExplicitO365Endpoint and value of 1.
BTW, I am using Microsoft Office 2016
not Office 365.
The solution was to go to Windows Start icon, then to Settings and then to Accounts and press "Sign in with a local account instead". Restarted the computer and then go again to Windows
Start icon, then to Settings and then to Accounts and press Login using Microsoft account. And after that the problem was gone and for two days now it didn't happen again.
So the problem was related to the authentication on the machine. To be more specific I used to logged in with my Microsoft account but at some point I chose not to login using the PIN or the Fingerprint because the
PIN seemed too easy to guess by someone watching me typing it. And the Fingerprint almost never works on my computer even if it's a Lenovo X1 Carbon. So I managed to somehow move back to password authentication method when I login on this computer. But the
system somehow messed up the authentication method during a windows or security updates and it started to behave like a full system amnesia. But now after logging out from my Microsoft account, login with a local account and then login back with Microsoft
account the problem was solved.
I must say that while the system amnesia, from time to time I got a notification saying that there seem to be a problem with my Microsoft account and asked me if I want the system to fix it. I pressed many times
the button Yes, I want the system to fix it and in that specific moment the system replied that it was fixed. Indeed it was asking me to input the PIN or the Fingerprint. After inputting the PIN everything seemed to be fine. But actually it wasn't. Because
when opening MS Word or Excel, the icon showing my name had a notification saying that I am not authenticated and was asking me to introduce the same PIN or Fingerprint. I entered the PIN many times but after restarting Word or Excel the problem was there
again. Now after logging out from my Microsoft account, login with a local account and then login back with Microsoft account this problem was solved too.
I hope this helps everybody experiencing similar issues.
Cheers!
Romulus