Accessing Outlook on the web for business using organizational credentials.
Hi Student Tübingen,
Thanks for the update. Please try Online Repair Office application to troubleshoot this issue. See Repair an Office application
After online repair, create a new Outlook profile and set up email account to see whether the problem still occurs. See under Create a new profile
Note: Please do not delete the old profile and can refer to it to get the new one set up. Once you have the new profile set up, you should select to “Always use this profile” option.
If the troubleshooting steps doesn't help, you may please create a new Windows user account and performing a clean install the latest Outlook desktop application program to set up email account see whether the problem still occurs.
Moreover, if your IT department manage Windows account creation/Office 365 installation then I would suggest you please contact them for further assistance.
Your patience and cooperation will be highly appreciated.
Best regards,
Shyamal