Solution: Disable Anti-virus Add-ins at MS Outlook to fix.
How to disable the MS outlook Add-ins
If you don’t want to use an add-in in MS Outlook 2013 / 2016 / 2019 for Windows, you can disable it so it won’t show up in your messages.
- In Outlook, click File > Manage Add-ins.Tip: This opens Outlook on the web.
- Under Manage add-ins, in the Turned on column, uncheck the box for the add-in you want to turn off.
Tip: To turn the add-in back on, check the same box.