It appears that this error can appear for a variety of reasons. Most commonly it seems to be due to invalid credentials or an issue communicating with a remote repository.
If you are certain your issue is not with remote communication, the problem might be that your image is failing to start. I have not had a chance to look into it but a better error message for this would be a great contribution to Minishift, if possible.
Test Docker Image Manually
To verify your docker image is working, try to run it manually.
Find the Image
Run: $ docker images
You should see a list that contains the image Minishift is trying to deploy. For example:
REPOSITORY TAG IMAGE ID CREATED SIZE
repo-name:port/app-name 1.0.0-SNAPSHOT-20190103151332485 3e050126264c 14 minutes ago 704MB
repo-name:port/app-name 1.0.0-SNAPSHOT-20190103150418331 4293956e114f 23 minutes ago 704MB
repo-name:port/app-name 1.0.0-SNAPSHOT-20190103145227835 81fc7783e38f 35 minutes ago 704MB
repo-name:port/app-name 1.0.0-SNAPSHOT-20190103145203603 c5fa4815ee97 35 minutes ago 704MB
Run the Image
Once you have identified the Image ID of the image you are trying to deploy, run:
$ docker run -i -t <Image ID> /bin/bash
For example:
$ docker run -i -t 3e050126264c /bin/bash
Diagnosis
If the image fails with an error, you have likely located the problem with your Minishift deploys. Diagnose the issue until you have a healthy image then try to deploy again.
In my personal instance, I find it most reliable to delete the old application from Minishift before deploying a healthy version.