In Settings, Bindings, and Ports. I have these setup and all ports are active. But when we have people connecting with IMAP on Desktop/Mobile you can not connect with SSL/TLS or StartTLS options so I am thinking I need to do something different as we want the secure. If they choose "None" everything works.

All are setup similar to the below. I have tried both SSL/TLS and StartTLS as options. None works as well.