Hi @Flórida da Graça Botelho Araújo ,
"Viewing of .pdf files has been disabled in Microsoft Word Mobile Viewer".
This problem occurs because PDF viewing on mobile browsers is not supported in Office Web Apps or Office Online Server.
Reference:https://learn.microsoft.com/en-us/office/troubleshoot/office-suite-issues/mobile-viewing-pdf-files
But your problem is that this problem also occurs on the desktop PC. It seems this is not a common issue per my test. However, we can work together to narrow down and resolve the situation. So, Please kindly provide more information below to let us work further.
1.Try to view a different PDF
2.Try to open with web browser or your browser's InPrivate mode
3.Restart your computer and try opening the PDF again
4.May I know if all users in your organization have this problem?
Hope the information can help you. And if there have any unclear or misunderstanding, please feel free to post back and we’ll continue to help you all the time!
Your understanding and patience will be highly appreciated! Hope you have a good day and keep safe!
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