Setting up Enterprise to Docker instances

Continuing the discussion from Setting up Redundancy between two Docker instances

I want to add these two docker instances (or only the master) as agents to my Enterprise setup but i'm not able to select agent in the EAM configuration on the docker gateway.

I was able to set up communication between the docker instances and my EAM Controller

so some kind of communication is possible between the two.
Has someone an idea what's missing?

You should be able to click here to set up the gateway as an EAM agent:

If that isn't there, can you confirm that the EAM module is installed on the gateway?