Full analysis if the problem
The root cause behind this problem is the delay in sync between CUCM and CCX.
CCX and CUCM has an automated sync mechanism which might vary from 5 - 10 minutes based on various parameters.
Also there is an option to sync newly added configuration manually, between CCX and CUCM for this scenario, when we delete an existing agent.
We can follow below approaches to avoid the issue reported,
Approach 1:
Step 1:
From CCX -> Consider an agent(Let’s say, agent1)from RmCm Resources List which has a device with IPCC extension(let’s say, 10001001) associated with it.
step2:
Under CUCM-> From End users list-> go to agent1 end user configuration -> Disassociate the IPCC extension(i.e. 10001001) from Directory number Association.
Create a new End user-> Associate the same device which was associated with agent1(old agent which had DN 10001001) to newly created agent-> associate same IPCC extension as 10001001 to the new agent.
Step 3:
On Finesse-> Wait for 10-15 minutes(i.e. Automated sync mechanism takes place)-> Login with new agent credentials and IPCC extension associated with it -> Successful Login
Approach 2:
Step1:
Follow step 1 and 2 from Approach 1.
Step 2:
Go to CCX-> Manually refresh the RmCm Resources List(i.e. manually refreshing resource list creates sync between CCX and CUCM resource list configuration)
Step 3:
On Finesse-> Login with new agent credentials and IPCC extension associated with it -> Successful Login
The behavior which we observe for this issue, is as per design and I have verified it across the releases from 11.6.2 to 12.5.
Please let me know if u have any further questions. Would suggest you to explain this behavior to customer and proceed to closures
