gate1*CLI> show channels
Channel (Context Extension Pri ) State Appl. Data
Zap/1-1 (from_bell s 1 ) Up Bridged Call Zap/101-1
Zap/101-1 (from_dialogic 12015537210 1 ) Up Dial Zap/g1/12015537210
Zap/99-1 (from_dialogic s 1 ) Up Bridged Call Zap/13-1
Zap/13-1 (from_bell 7458 1 ) Up Dial Zap/g5/7458
4 active channel(s)
-- Accepting call from '5145556663' to '1909' on channel 0/23, span 1
-- Executing Dial("Zap/23-1", "Zap/g5/1909") in new stack
-- Called g5/1909
-- Channel 0/1, span 5 got hangup
-- Zap/97-1 is busy
-- Hungup 'Zap/97-1'
== Everyone is busy/congested at this time
-- Channel 0/23, span 1 got hangup
-- Hungup 'Zap/23-1'
gate1*CLI>
why Zap/97-1 is busy exactly?