Attempted to send call to agent: (ID: ), on peripheral: (ID: ), who has no device target.

If you receive an error like this:

Attempted to send call to agent: ccondry_0 (ID: 5050), on peripheral: CUCM_PG (ID: 5000), who has no device target.

Then you need to add the Routing Client in question to the Agent Targeting Rule you have set up for the agent device. Here is a screenshot of the button to add more routing clients to an existing Agent Targeting Rule: