Twinkle phones not recieving incoming, but can place calls

Hey everyone,
Getting my asterisk server pretty close to 100% production level stability, however somehow it seems to dislike the twinkle softphones. Why I am not sure, however, when you call the extension that the twinkle phone is using it goes straight to voicemail and no ringing.

I can also call other hard phones, and the Xlite softphones no problem that are setup the same way. Asterisk problem?

Below is the output from the CLI.

Executing [4001@default:1] Dial("SIP/4001-b770f098", "SIP/4001|20|") in new stack
    -- Called 4001xit
[Apr  4 15:21:09] NOTICE[7477]: chan_sip.c:2880 auto_congest: Auto-congesting SIP/4001-09c09f90
    -- SIP/4001-09c09f90 is circuit-busy
[Apr  4 15:21:09] NOTICE[32216]: cdr.c:434 ast_cdr_free: CDR on channel 'SIP/4001-09c09f90' not posted
  == Everyone is busy/congested at this time (1:0/1/0)
    -- Executing [4001@default:2] VoiceMail("SIP/4001-b770f098", "4001@default") in new stack
    -- <SIP/4001-b770f098> Playing 'vm-intro' (language 'en')



how about your show peers result? what’s your 4001’s status?

The peers are all registered and alive and kicking. I have no idea why other soft phoens work and htis one won’t.