eM Client does not use most recent certificate from mail server

Since a few days, eM Client gives a "eM CLient can’t verify identity of " error whenever I restart it. It shows an outdated certificate which is of course no longer valid.
But I checked with //email/testTo: and SSL Checker, and the mail server does respond with a new valid certificate.

Why does eM Client still use the old certificate instead of the new one?

What version of eMC are you using?

8.2.1659 (845a639), the most recent version afaik.

What is the complete error?

cert

Certificate expired on November 16, when the error message started. New certificate that is issued by the server is valid till 30/1/2022. Expiry date 16/11 was or the previous certificate.

Hopefully someone else will have knowledge of how these certificates work, but until then perhaps, IF you are using IMAP, you can remove the account and re-add the account.

FYI, you can find the exact version using: MENU > HELP > ABOUT

I am using POP3.
The version came from menu->help->about.

I just detected that on another PC with the same version of eM Client, I don’t have the issue.

Have you tried uninstalling and reinstalling? If you want to try that do an eMC backup(Menu > Backup), uninstall (do not delete database), install from HERE

I will try reinstalling later. I was now focusing on why it works on one PC and not the other.
I found that the error is not for any of my email accounts, but for a calendar account. I have a CalDAV/CardDAV account setup on the same server as the mail server.
In eM Client’s calendar view I see the red triangle with exclamation mark indicating an issue.

Is there a known issue with calendars in em CLient?

I seem to have hit the CalDav Certificate Error issue.

That is an issue with earlier versions of eM Client on Windows 11.

You will need to upgrade to the latest version of eM Client here: https://www.emclient.com/dist/v8.2.1659/setup.msi

I am still on Windows 10.0.19042.

Have you maybe disabled TLS 1.2?

If so, please enable it again and see if there is any difference.

The mail server on cpanel 98, which has TLS 1.2 always enabled. //email/testTo: also reports that “SSLVersion in use: TLSv1_2”.

I meant on your PC, not the server.

On my PC, in Internet Properties->Advanced->Security, I see that SSL 3.0 and TLS 1.3 are disabled. TLS 1.0, TLS 1.1 and TLS 1.2 are enabled.