I have just setup my university mail to use Mail.app, but the certificate seems to be invalid. Basically every time Mail.app loads it comes up with the certificate invalid window

I have founnd the instructions in the help window below except added the certicate to X509anchors as X.509 Anchors doesn't exist

what am I doing wrong?

I have founnd the instructions in the help window below except added the certicate to X509anchors as X.509 Anchors doesn't exist

what am I doing wrong?