Retrieving layer already exists error while pushing docker image

  docker, gitlab, gitlab-ci, travis-ci

I am having issues with building and pushing my docker image to GitLab, (Layer already exists) even after I have forced removed any previous images. when I make changes to code and git push, the code is updating on the GitLab repository, however, when I rebuild and push the image to the GitLab registry, the code doesn’t take effect.

Source: Docker Questions