I have problems with an invalid certificate. All other mail programs do not have any issues but E client does. If I click “show certificate” and tell the software, that it can be trusted, the program crashes and I have to do a reset.
If I click “connect”, it works but the message comes again on the next program start.
This is a certificate on your email provider’s server. It is not setup correctly, so has been flagged as a security risk.
You need to contact your email provider and ask them to fix it for you.