Getting the configuration from an ATLAS is complicated, because you can't simply print it out, like our AOS devices.
Since it's a PRI to FXS ports, it should all be configured under the DIAL PLAN. If you look at the NETWORK TERM, you should see your PRI. There is an OUT#ACCEPT there, that lists what numbers will be accepted to go out the PRI, as well as an OUT#REJECT list (this is a list of numbers that will be blocked from going out the PRI). If you have "$" in the OUT#ACCEPT, that means it will accept any number dialed. If it has "--" then it will not allow anything.
If you only want to allow 1 FXS port to dial out, then you can set that FXS port (under the DIAL PLAN, USER TERM, and IFCE CONFIG) with a specific SOURCE ID (the default is "0" so I would change it on this one rather than change the Source ID on all the other entries - change it to "1"), then under the NETWORK TERM and OUT#ACCEPT, set the SOURCE ID to "1" to allow anything with a Source ID of 1 (in this case the FXS port you changed in the USER TERM) to dial out the PRI.
If you leave everything at SOURCE ID of "0" then any of the ports will be able to dial out.
Hope this makes sense,
I followed your steps and noticed that my PRI was set for source 7, changed the FXS port to source 7 and outbound calls now work.