[Outlook add-in problem]

Had a second user hit me up this morning and she did have Endpoint Security installed. Just disabling Sent Email did not fix the issue. It did have to be both options as you previously mentioned. So depending on the ESET being Endpoint Security or Endpoint Protection it might require both being disabled to fix.

But it does look like disabling those settings resolved the issue.

[Outlook add-in problem]

Disabling sent email (first screenshot) seemed to resolve the issue. I was unable to find the option in the second screenshot to disable, but it seems it was not needed.

[Outlook add-in problem]

Screenshots attached of all installed add-ons.

[Outlook add-in problem]

Experiencing the same issue with outgoing emails being blank. Disabling ESET addon resolved the issue as a temporary fix. There was not an Egress Switch addon installed for outlook.