I think it coluld be, because in the default configuration Asterisk 1.4 use # for unattended transfers and * for hangup, so check the section featuremap in features.conf to see if/what this dtmfs are used for.
You’re right, by default asterisk uses # for blind transfers and * for disconnecting.
After changing the values to #1 and *1 and a restart of the asterisk daemon, the issue still occurs:
-- Executing [0*#20001234567890@test:1] Dial("SIP/9010-08bcdf00", "Zap/g1/*#20001234567890") in new stack
-- Requested transfer capability: 0x00 - SPEECH
-- Called g1/*#20001234567890
-- Zap/1-1 is proceeding passing it to SIP/9010-08bcdf00
-- Channel 0/1, span 1 got hangup, cause 1
-- Hungup 'Zap/1-1'
== Everyone is busy/congested at this time (1:0/0/1)
== Auto fallthrough, channel 'SIP/9010-08bcdf00' status is 'CHANUNAVAIL'
I do not log in with an agent to make these calls, but i changed