Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Hi FreekDomenie,
Greetings, since you post your question in the English forum, I will use English to answer your questions.
By using the translation tool, I learned that you received an error message when using Outlook. Regarding the error message you received, please kindly do following steps to see if it can help you fix this issue: open Outlook client and go to File > Info > Account Settings > Account Settings > Internet Calendars, then delete the issued calendar.
If the issue persists, please close Outlook and press Windows key + R and then copy and paste the following command in the Open box, and then press Enter:
Outlook /cleansharing
If above methods cannot help you fix this issue and you need further assistance, please send us a screenshoot of the error message for analysis.
Meanwhile, if convenience, it is recommended to post your reply in English so we can assist you better. Or you can post a new thread in the correct category in below link and other engineer will continue to help you:
Thanks for your understanding and cooperation.
Regards,
Jennifer