Can't connect to agents in queue


When doing a predictive dialing, calls are not being connected to agents in queue. Following is the error getting

[Jul 5 16:32:26] WARNING[17549] app_dial.c: Unable to create channel of type ‘SIP’ (cause 20 - Unknown)
[Jul 5 16:32:26] VERBOSE[17549] logger.c: == Everyone is busy/congested at this time (1:0/0/1)

Please advice me to resolve this issue.