In the past I have skipped the port when specifying images in .gitlab-ci.yml.

some-build-job:
  stage: build
  image: server/image:tag

After a new gitlab installation I have to add the port.

some-build-job:
  stage: build
  image: server:5000/image:tag

Is there a place where the default port can be set to 5000 such that it can be omitted in the image name when writing ci scripts as before?

It is a local gitlab installation in an isolated docker network. Is the origin of the problem maybe that ssh access to the registry is not enabled? If ssh access is enabled then the client (i.e. the runner) may be looking at port 443 by default and then the problem would disappear by itself?