Gitlab CI/CD fails to build docker image

I have built a custom base image from alpine and use it as the base for ruby services that we develop.

FROM ruby:2.4.2-alpine...

I use Gitlab and Gitlab's docker registry along with it. Each project has its own docker image storage.

I created a separate project for the alpine-ruby-service dockerfile. Then build and pushed the image to Gitlab.

In the ruby service project docker images, I reference it as follows

FROM gitlab.mycompany.dk/alpine-ruby-service-base...

I have a CI/CD pipeline (.gitlab-ci.yaml) which builds these ruby service images when there is a commit to one of the branches.

The problem is that when the CI/CD pipeline is run it fails with the following message

 $ docker build --pull -t $CONTAINER_TEST_IMAGE .   Sending build context to Docker daemon  709.6kB Step 1/13 : FROM gitlab.mycompany.dk:xxxx/alpine-ruby-service-base pull access denied for gitlab.mycompany.dk:xxxx/alpine-ruby-service-base, repository does not exist or may require 'docker login': denied:  requested access to the resource is denied

I have an instruction to login to the Gitlab docker registry before the build command above using

 docker login --username=gitlab-ci-token --password=$CI_JOB_TOKEN gitlab.mycompany.dk:xxxx

the login succeeds but the following docker build instruction fails!!! can someone point me what is going wrong?