diff --git a/.gitea/workflows/prod-docker-images.yml b/.gitea/workflows/prod-docker-images.yml
index 0bfe4e3..059d68f 100644
--- a/.gitea/workflows/prod-docker-images.yml
+++ b/.gitea/workflows/prod-docker-images.yml
@@ -26,12 +26,15 @@ jobs:
         id: VERSION
         run: echo "VERSION=`cat VERSION`" >> $GITHUB_ENV
 
+      - name: Convert repository owner to lowercase
+        run: echo "REPO_OWNER_LC=$(echo '${{ gitea.repository_owner }}' | tr '[:upper:]' '[:lower:]')" >> $GITHUB_ENV
+
       - name: Build and push Docker image for latest tag
         uses: docker/build-push-action@v6
         with:
           context: ./build
           push: true
-          tags: ${{ vars.DOCKER_REGISTRY_URL }}/${{ gitea.repository_owner }}/protonmail-bridge:latest
+          tags: ${{ vars.DOCKER_REGISTRY_URL }}/${{ env.REPO_OWNER_LC }}/protonmail-bridge:latest
           platforms: linux/amd64
           build-args: |
             VERSION=${{ env.VERSION }}