Outlook certificate errors be like:

[0xabad1dea@infosec.exchange]

Outlook certificate errors be like:

The certificate is not signed by an authority you trust, and in fact is signed by the Alien Alliance for Human Destruction.
The certificate uses an algorithm deprecated in 1876 due to being solvable on paper by bright kindergarteners.
The expiration date is notated in a calendar unknown to our science.
The certificate has a valid name