Unable to create channel of type 'DAHDI' (cause 34 - Circuit/channel congestion)

I use ‘asterisk 13.21’ and sometimes I got a warning:

app_dial.c:1450 dial_exec_full: Unable to create channel of type 'DAHDI' (cause 34 - Circuit/channel congestion)

This warning is very often meets with on different hardware cards (Sangoma, Digium etc). Also problem meets on wide range of asterisk version from 1.4 till 15.x.

What’s a real problem in this case?
Maybe somebody knows solution of it.
Any suggestions are welcome.

As you have test with many cars and still issue, and based on the hangup cause

Code No. 34 - no circuit/channel available.
This cause indicates that there is no appropriate circuit/channel presently available to handle the call.

You should contact your telcom, or address the support for this issue directly with the card vendors, through their support channel, we dont provide card support on this forum

Thank you ambiorixg12.

By the way, google have a lot links to this question without a clear answer.