My Services are being registered on jhipster-registry. As can be seen below:
As you can see, Canoja service and Gateway are registered in my service registry. And as per the documentation:
The gateway will automatically proxy all requests to the microservices, using their application name: for example, when microservices app1 is registered, it is available on the gateway on the /services/app1 URL.
I was expecting the gateway to pull my service APIs automatically. But, my APIs are not available in the gateway:


I had the same problem, apparently the problem was with the names of the registered microservices (they were too long).
I was using a generated gateway that was generated using JHipster 7.9.3, and a registry version 7.4.0, and all the microservices were created using jhipster 7.9.3 as well.
Sadly, i cannot provide any logs whatsoever because the gateway was displaying no logs whatsoever, just the fact that it fails to route because no instance of the called service was found.
TLDR: try to make each service name between 3 to 8 characters and no special characters.