Incoming call not landing to free agents

[urmi.l]

Hello,

We have installed centos 6.8 and scratch install of vicidial 2.11 version.

We have one campaign having many ingroups. All the agetns are having on hook features enabled.

When first incoming call comes its ringing on one agent's phone extension and its working fine.
If there at the same time another few more calls are coming then those calls are not ringing to any of the extensions till the first call gets answered or hangup. Queue calls not ringing on my ready agents phones.

We have NEXT AGENT CALL - Logest wait time.

Can you please suggest us.

[urmi.l]

Any help ?