Linksys PAP2

I can’t seem to get this to work. I’ve got my FreePBX behind a pfSense router (not using siproxyd, port forwarded 5060-5063, and 10000-20000 on a Brighthouse cablemodem), and a linksys PAP2 behind a Verizon modem, ports 5060-5061, 10000-20000 forwarded. At first, line 1 comes up, no problems with audio. Line 2 comes up, but calls terminated to the linksys have one way audio (calling party can’t hear). Calls originated from the linksys there aren’t any problems. After a while, same problem on line 1.

Asterisk is configured with externip correctly. Linksys is configured with STUN and reports correct external IP.

I suspect this a problem with the verizon router, but I need to confirm it.

Any other suggestions? Thx.