Intel AMT Redirection port (16994 for non TLS / 16995 for TLS setup) is used by Intel AMT SOL, IDE-R/USB-R and KVM Redirection sessions.
this port listener state shall be enabled by redirection application console. It is not AMT configuration parameter so you can't enable it as part of AMT setup.
After AMT configuration from full unprovisioned state Redirection Port Listener state will be Disabled (off).
In MEBx setup you may select Legacy Redirection Mode = Enabled which will turn on AMT Redirection Port.
If it is not enabled Manageability Commander Tool MESH Edition (use v0.1.35) will gray-out Take Control button.
You have to enable it from Remote Control Tab or via RedirectConfig.exe tool from Intel AMT SDK.
In Manageability Commander Tool MESH Edition you have also activate IDE-R session from AMT Terminal after selecting IDE-R FDD & CDD/DVD images/media click Disc Redirect > Redirect Active.
MeshCommander will display information about Redirection Port being disabled on the top of Redirection(SOL/KVM) window - you shall check Redirection Port
Last but not least - you have to use FQDN of target PC for Intel AMT TLS connections - and make sure your console trusts all AMT TLS cert trust chain.