Hi @Aafje van den Boogert ,
Since the tag office-itpro focuses on general issues about Office desktop applications, I suggest you post this issue to Office for Android:
https://answers.microsoft.com/en-us/msoffice/forum/msoffice_install-msoffice_unknown-mso_OPandr
Or Office for iPhone or iPad:
https://answers.microsoft.com/en-us/msoffice/forum/msoffice_install-msoffice_unknown-mso_OPiOS
The reason why we recommend posting appropriately is you will get the most qualified pool of respondents, and other partners who read the forums regularly can either share their knowledge or learn from your interaction with us. Thank you for your understanding.
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