Microsoft 365 Mac muss jeden Tag aktiviert werden

Es tut mir Leid, ich habe übersehen, dass MS mich automatisch auf die deutsche Seite umgeleitet hat... Ich spreche Deutsch, also können Sie / könntet Ihr auf Deutsch antworten.

I have had Office 365 for Mac (I have a corporate E5 license) on my MacBook Air M4 since its purchase in March 2025. Since October it requires constant reactivation.

Outlook allows itself to be activated in "New" mode, as soon as I switch back to legacy (for on-premises accounts Outlook New can't convert), it wants to be activated again, but only displays the "signon" window with the animated circle and "Loading...".

Excel and Word do the same, they ask to be activated, then display the signon windows with rotating circle and "Loading...". I have left it running for up to 3 hours and nothing further happens.

Doing the following brings short term relief:

• Deinstall Office 365
• Delete all Microsoft Office files and folders in the user Library folder
• Delete all Microsoft Office entries in the Apple Keychain
• Run the Microsoft Office License removal tool
• Restart the Mac
• Reinstall Office 365 for Mac
• Activate without problems

After that, it will run happily for 2-4 days, after which I have to go through the whole deinstallation and reinstallation process again!What is going on? Why won't it stay activated and why, once activated, does it not display the activation dialog properly, when it needs re-activating in a couple of days?

Note: The activation dialog will display normally and allow me to sign on the first time, after that it just shows "loading..." when it asks for activation the next time. Once Office has been completely removed and reinstalled the activation dialog works again, so it has nothing to do with networking (firewall, proxy, AV software etc.).

I have also made my account and admin, that didn't help.

I have also completely disabled the Sophos AV software, that didn't help.