Outlook The Security Certificate Was Issued By A Company You Have Not Chosen To Trust 【99% PROVEN】

If the answer is "No," Outlook slams the brakes. This usually happens in three specific scenarios:

Before clicking anything, click Look at two things: If the answer is "No," Outlook slams the brakes

Office 365 and newer Exchange versions use OAuth 2.0, which handles certificate trust differently and rarely triggers this error. When a certificate is presented, Outlook checks: Is

Outlook (and Windows) maintains a list of "Trusted Root Certification Authorities." These are global companies like DigiCert, GlobalSign, or Let's Encrypt. When a certificate is presented, Outlook checks: Is the issuer on my trusted list? When a certificate is presented

: Your IT department or hosting provider is using a "home-made" certificate that isn't recognized by global trust authorities.

Here is how to tell the difference:

Decoding the Outlook Nightmare: "The Security Certificate Was Issued by a Company You Have Not Chosen to Trust"