Shared Calendars are not loading in Outlook

[YvonneP]

Since Thursday multiple our users reported the following issue:
While using the old Outlook, the shared calendars are not loading, they are always showing "updating". 
The workaround we use is to switch to the new outlook (which is awful) or suggest to use the MS Teams meeting assistant.  

We are using Office 365/Exchange online.

Does anyone else currently have to deal with this issue? Is there a known solution?

[#2]

Some of our users report that, too. My entry point was throttling. Because user reported the same issue some weeks or months ago. And indeed it seems like I can temporarily work around the issue with a script that wipes away all Outlook Windows configuration from the user profile (HKCU Software, appdata and localappdata). However the problem keeps coming back.
By the way we have calendar improvements disabled by policy.

[#3]

https://www.borncity.com/blog/2024/03/15/probleme-mit-microsoft-outlook-terminplanung-seit-mrz-2024-...