[Asterisk-Users] ZAP/PRI Error: channel reported in use

[Chris A. Icide]

I have a system with two 4 port T1 cards, with 5 PRI's configured.  Each 
PRI is configured as an individual PRI and belongs to it's own group 
(groups 1-5)

This system is handling roll-over from another system, where any error in 
processing the call on that system results in it being sent here.  This 
mainly results in all calls resulting in a busy being sent for retry 
here.  I then try the groups in order, 1-5.  However, spans 2,3, and 4 are 
erroring out with a strange error.  They are configured the same as 
circuits 1 and 5, and the carrier claims they are all configured the same.

The error I'm concerned with it this:

     -- Forcing restart of channel 0/21 on span 2 since channel reported in use

See error in context below.

    -- Executing Dial("IAX2/unipoint-4 at unipoint-4/1", "Zap/G1/5551212") in 
new stack
     -- Called G1/5551212
     -- Channel 0/23, span 1 got hangup
     -- Zap/23-1 is busy
     -- Hungup 'Zap/23-1'
   == Everyone is busy/congested at this time (1:1/0/0)
     -- Executing Dial("IAX2/unipoint-4 at unipoint-4/1", "Zap/G2/5551212") in 
new stack
     -- Called G2/5551212
     -- Channel 0/21, span 2 got hangup
     -- Forcing restart of channel 0/21 on span 2 since channel reported in use
     -- Hungup 'Zap/45-1'
   == No one is available to answer at this time (1:0/0/0)
     -- Executing Goto("IAX2/unipoint-4 at unipoint-4/1", "203") in new stack
     -- Goto (unipoint,5551212,203)
     -- Executing Dial("IAX2/unipoint-4 at unipoint-4/1", "Zap/G3/5551212") in 
new stack
     -- Called G3/5551212
     -- Channel 0/21, span 3 got hangup
     -- Forcing restart of channel 0/21 on span 3 since channel reported in use
     -- Hungup 'Zap/69-1'
   == No one is available to answer at this time (1:0/0/0)
     -- Executing Goto("IAX2/unipoint-4 at unipoint-4/1", "304") in new stack
     -- Goto (unipoint,5551212,304)
     -- Executing Dial("IAX2/unipoint-4 at unipoint-4/1", "Zap/G4/5551212") in 
new stack
     -- Called G4/5551212
     -- Channel 0/21, span 4 got hangup
     -- Forcing restart of channel 0/21 on span 4 since channel reported in use
     -- Hungup 'Zap/93-1'
   == No one is available to answer at this time (1:0/0/0)
     -- Executing Goto("IAX2/unipoint-4 at unipoint-4/1", "405") in new stack
     -- Goto (unipoint,5551212,405)
     -- Executing Dial("IAX2/unipoint-4 at unipoint-4/1", "Zap/G5/5551212") in 
new stack
     -- Called G5/5551212
     -- Channel 0/22, span 5 got hangup
     -- Zap/118-1 is busy
     -- Hungup 'Zap/118-1'
   == Everyone is busy/congested at this time (1:1/0/0)
     -- Executing Hangup("IAX2/unipoint-4 at unipoint-4/1", "") in new stack