You’re using Chan-SIP, so that’s not cool. You probably need to switch this to PJ-SIP.
Unless your ITSP is in your local network, I don’t think those settings won’t work. You can verify this by checking your /var/log/asterisk/full logs to see what’s happening with your incoming calls.
If you are going to keep using Chan-SIP, you should set this up as a single config in the PEER settings and use a “type=friend” so that the settings are shared with your incoming and outgoing.