Hello,
Well, obviously you want to know what really happens on the interfaces --
- run tcpdump against both ports (for internal and external profile) separately, try to register/call from the device you use
- check 'sofia status' - it'll show you ports freeswitch (and especially sofia) is running on, check that with your configuration
- if phone is not contacting the pbx, you have network problem you have to fix first
- if your phone is contacting freeswitch, increase log level and see what happens
- try turning 'siptrace on' on both sofia profiles
Generally, not enough data; and by the way - if you can, try running FS 1.6 - it's... well, yes, even FS 1.0 will work, but to harness all the FS power and use all its funky features (last but not least: and have your FS patched), use something recent.
...last but not least: if your pbx is reachable from the Internet PLEASE use fail2ban and other measures to reduce chance of abuse.
Cheers!