We now need to use TLS in Outlook 2010 for email - according to the provider we only need port 995 open. Have that open to all systems, but we get "The computer does not support the encryption type" error. Move the system outside the firewall and it works perfectly. Any idea what needs to be allowed through to support TLS encryption? Thanks!
Please look at the below link for more details on this:
If you are running a version older than 8.0(3) on the ASA, you will need to disable esmtp inspection if you have it. If you are running 8.0(3) or later, you will have to create a Layer 7 classmap/policy-map and specify an action of "allow-tls" as given in the below link.
If you do not have inspection for esmtp configured, we will need to get captures in both the situations and compare those. Hope this helps.
All the best!!