MacOS – “Connection insecure” error when trying to manage a Gmail or Yahoo account

accountsgmailmacosyahoo

About a week ago, I was prompted to reset my Yahoo e-mail password. So I went to System Preferences -> Internet Accounts and double clicked on Ymail (the Yahoo e-mail account). I saw this screen:

Ymail empty

Followed shortly by this error message:

Connection Insecure. Failed to verify the server certificate. This could be because of your network configuration or your proxy settings.

Dismissing the error message does nothing to the first window, and eventually I have to cancel.

Strangely, I noticed this same behavior has happened when I double-click on my Gmail account, despite the fact that the password still seems to be valid.

I have seen this behavior both at my home and my local coffee shop. To my knowledge, I am not using a proxy. What can I do to solve this "Connection Insecure" problem when trying to manage a Gmail or Yahoo account?

Best Answer

Check the Login/Certificates container in the keychain for anything with a red mark that says "Certificate is invalid". It's probably an old CA on the box that's conflicting with the current one from those accounts.