Line 2 outbound

I have a Carrier giving me 2 lines FXS, and I run that into 2 FXS ports on my FreePBX server.
Line 1 functions as advertised.
Line 2 will give a busy signal when making outbound calls. Always. Not inbound- those work fine. But no outbound service. The routes go to my POTS trunk, and everything else seems to be right.
What have I messed up?

Tony

FreePBX support is provided through https://community.freepbx.org/

Analogue port support is provided through the commercial channels of the hardware vendor.