Sometimes transfer to the agent fails with RESOURCE_BUSY. We may sometimes see the agent toggling between reserved and ready due to this.
Ideally this should never happen as Unified CCX only finds free agents and routes calls to them.
But this could happen if for some reason a call is stuck on the agent's phone from JTAPI/CTI perspective.
Max call setting on agent extension is 1. So if a call is stuck on the agent phone then the next call which Unified CCX tries to send to the agent from the queue will fail with RESOURCE_BUSY
The best way to troubleshoot such issues is to find the last call that was successfully transfered to this agent and trace the flow to see if the call ended properly.
If there were any JTAPI exception in that previous call then this case can be escalated to IPCBU JTAPI team.
But sometimes, the previous call may have been cleaned up by RmCm cleanup thread for some reason. In such cases, this can be escalated to Unified CCX ICD team. Or if analysing the previous call turns too hard then this case can be escalated to Unified CCX ICD team so that the experts can take a look.