gitea action build and push docker image results in failed to push with 404 error

I've created a gitea action to build and push a docker image to the docker registry hosted in gitea. When pushing the image, the task returns the follwing error:

ERROR: failed to solve: failed to push my.domain.com/ebooks:ae374c5d690cd6b29b4c91752e7998ed6539365a: unexpected status from POST request to https://my.domain.com/v2/ebooks/blobs/uploads/: 404 Not Found ::error::buildx failed with: ERROR: failed to solve: failed to push my.domain.com/ebooks:ae374c5d690cd6b29b4c91752e7998ed6539365a: unexpected status from POST request to https://my.domain.com/v2/ebooks/blobs/uploads/: 404 Not Found

This is the build task:

name: build
run-name: build
on: [push]

jobs:
  build:
    runs-on: default
    steps:
      - uses: actions/checkout@v4
      - name: setup docker buildx
        uses: docker/setup-buildx-action@v3
      - name: login to container registry
        uses: docker/login-action@v2
        with:
          registry: my.domain.com
          username: ${{secrets.USER}}
          password: ${{secrets.TOKEN}}
      - name: build and push docker image
        uses: docker/build-push-action@v5
        with:
          context: .
          file: ./Dockerfile
          push: true
          tags: "my.domain.com/ebooks:${{gitea.sha}},my.domain.com/ebooks:latest"

I am irritated by the v2 in the url of the error message. Could it be, that I'm using the wrong build action (docker/build-push-action@v5)? If so, what would be the correct one?

The steps before (docker login) are working correct.

found the solution by myself. Gitea needs the organisation in the tagname. So instead of the tagging: "my.domain.com/ebooks:${{gitea.sha}}"

it also needed to use the organization: "my.domain.com/organisation/ebooks:${{gitea.sha}}"