Outlook not connecting, secure certificate error


Hi Everyone,


I have one PC where Outlook won't connect to an Office 365 user account.


This user account can be setup under Outlook on other PCs without issue.


When going through the Outlook profile setup the following secure certificate error is show (the domain looks very suspicious).




Can someone please help me with fixing this one?



3 Replies

Is the PC domain join or is it there personal computer? And is the computer running anti-virus?
best response confirmed by telecaster (Contributor)

Looks like something dodgy on the PC, I would just give the user a clean machine and see if that works. If so, wipe the old one.

@CloudHalThis issue turned out to be fixed by optional Windows Update October 24, 2019—KB4522355 (OS Build 18362.449).


Was very hard to troubleshoot but we go there in the end.