Queue sending no busy


i am using FreePBX 12.0.13.
My Problem at moment is that my queue will answer all calls eve if all agents are busy.
It looks like that _

ext-call —> queue is answering —> queue detects that all agents are busy --> queue is sending busy to the caller.
but i need it that the quete is not answering the call. in need it that the que is sending busy to caller without answering the call if all agents are busy.

Is there way ?

solved !

it was a failure in a2billing