Portech Gateway with FreePBX

Hey everyone,
I recently had an issue where a MobilinkIP GSM gateway was close to a lightning strike and fried.
Unfortunately I was unable to source a new one of the same make / model.
What I was able to do was source a Portech MV-372G.
I followed this guide to get things working and it all seemed fine.
Started to get calls that the incoming calls were coming through with no sound so I tested one and found that on the caller’s end, all you heard was ringing but when watching Asterisk logs, I could see call picked up, answered by IVR, and transfered to ring group. Call was picked up with silence on receiver’s end but still ringing on caller’s end.

Here is my setup.

Outgoing Settings

Trunk Name	SIM1

PEER Details

USER Context	SIM-1

I notice in asterisk logs that i see this every minute or so

NOTICE[1852]: chan_sip.c:28235 handle_request_register: Registration from '<sip:[email protected]>' failed for '' - Wrong password

Why is Asterisk trying to register with a user / pass ???