I'm sorry, I thought I replied to an existing topic, but it seems I instead started a new .
Anyway - my issue was that outlook desktop app kept showing 'disconnected' from server. It only happens on this computer, and it has been happening for a couple of weeks. When I disabled Anti-Malware it suddenly connected. I then tried to add 'outlook.com' and outlook.exe to the exclusion setting and enable AM, but outlook showed 'disconnected' again. Disabling AM and outlook connected.
Of course I cannot say for sure this happens because of Malware bytes, could be latest Office update or Windows update, but if I disable Malware bytes then it seems to work, at least so far.
The is no blocked IP popup message (I got that for Skype, but adding Skype.exe to exclusion fixed that), outlook just doesn't connect, and shows 'disconnected' in the status bar.
I will try and enable Malwarebytes again and disable preview as you suggest, maybe that will fix my issue.
Thanks
Jesper