Hello and welcome 
If the agent is not installed you don’t need to (or better must not) define an endpoint and a zone.
This is only necessary for hosts where Icinga 2 is installed, so that the instances can communicate directly.
So simply remove the endpoint and zone for the non-agent host, move it to the zones.d/master folder and delete the check for that hosts cluster-zone.
OR
Install the agent on the host and connect it to the master.
If you do that you need to install the check plugins, because then the checks are executed on the agent.
PS: In future posts please use markdown formatting to get a better readability when posting config snippets. A HowTo can be found here
Thanks