Uploading build docker image to another project

Uploading build docker image to another project in the same self hosted gitlab instance.

I am trying to build two docker images. One for rails restapi and one for sidekiq based on a rail restapi project for deployment. In the docker build job for rails project, in the same task, I build both images with a multistage dockerfile and first build rails api image and push to gitlab. Then based on the pushed image install nodejs to make it a sidekiq image. When I try to upload the sidekiq image to a dedicated project’s container registry. That fails with


#16 34.10 Setting up python2 (2.7.16-1) ...`
#16 34.12 Setting up libpython-stdlib:amd64 (2.7.16-1) ...` 
#16 34.14 Setting up python (2.7.16-1) ...`
#16 34.17 Processing triggers for mime-support (3.62) ...` 
#16 DONE 34.6s` 
#18 exporting to image`
#18 exporting layers` 
#18 exporting layers 1.7s done`
#18 writing image sha256:77b65c1bea17ae1ad0b3b21d5c4eeb0924d7fd4822759853b3446a48b0bc4f5c` 
#18 writing image sha256:77b65c1bea17ae1ad0b3b21d5c4eeb0924d7fd4822759853b3446a48b0bc4f5c done` 
#18 naming to xxxx.gitlab.de:4567/simoapi/core-app-sidekiq done` 
#18 DONE 1.8s`
 ` ------`
> importing cache manifest from core-app-sidekiq:` 
` ------` 
` $ docker tag core-app-sidekiq $CI_REGISTRY/simoapi/core-app-sidekiq/core-app-sidekiq` 
` $ docker push $CI_REGISTRY/simoapi/ejar3-core-app-sidekiq/core-app-sidekiq` 
` The push refers to repository [xxxx.gitlab.de:4567/simoapi/core-app-sidekiq/core-app-sidekiq]` 
` 4dcb072eacee: Preparing` 
` d57650f6af71: Preparing` 
` 8ce28c27028e: Preparing`
` a2a7b8b1e3a2: Preparing` 
` 9b3e5e507534: Preparing` 
` 4218fc764643: Preparing` 
` 1a151a286ed3: Preparing` 
` 55d1d0cddb22: Preparing` 
` 4ffcc982b204: Preparing` 
` 69ecf019f649: Preparing` 
` c3a984abe8a8: Preparing` 
` 4218fc764643: Waiting` 
` 4ffcc982b204: Waiting` 
` 69ecf019f649: Waiting` 
` c3a984abe8a8: Waiting` 
` 55d1d0cddb22: Waiting` `
 1a151a286ed3: Waiting` 
` denied: requested access to the resource is denied`*

`

using self-managed gitlab