Hi @Joey Godrie ,
Have seen this issue discussed in another thread here: Outlook 365 application error 1001, mail is not syncing
You can try the high voted solution shared there and see if it can work on your side:
- Close all Microsoft applications, office, teams etc.
- Go to your AppData folder and navigate to Microsoft (C:\Usersyourusername\AppData\Local\Microsoft)
- Cut/paste the OneAuth and IdentityCache folders out of the Microsoft folder and paste it onto your desktop.
- Relaunch Outlook and sign in. It might already be fixed at this point. If not, close out of Outlook, copy the OneAuth and IdentityCache folders back into the Microsoft AppData folder but.. when it asks if you want to overwrite, say NO.
- Relaunch Outlook and sign in, should be working now.
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