Hi @Bruno Barabaschi ,
What type of account are you using?
If you sign in to online, will it occur same error?
Please also kindly check whether you have updated your Outlook to the latest version, if not please try it and then check the result.
If the issue continues, try to create a new profile, and add your account to the new profile and check if the same error still occurs.
Outlook for Windows: Create an Outlook profile
Outlook for Mac: Manage profiles or identities in Outlook for Mac
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