buildx built the image but could not push it. failed to solve: failed to push <ref> means the registry rejected or could not receive the push - usually missing/expired auth, a repository that does not exist, or a transient registry error.
What this error means
A docker buildx build --push (or build-push-action with push: true) fails at the push with failed to solve: failed to push <ref>: ..., naming an auth, not-found, or server error.
docker
ERROR: failed to solve: failed to push ghcr.io/myorg/api:1.4.2:
unexpected status from POST request to https://ghcr.io/v2/myorg/api/blobs/uploads/: 401 Unauthorized
Common causes
Not logged in (or token expired) for the registry
A push needs valid write credentials for the target registry. A missing docker login, a wrong token, or an expired one fails the push with 401/403.
The target repository does not exist or is not writable
Some registries (ECR) require the repository to exist first; a namespace your token cannot write fails the push.
Transient registry error during upload
A 5xx or dropped connection while uploading blobs fails the push and usually clears on retry.
How to fix it
Authenticate with write scope before pushing
Log in to the exact registry with a token that can write the repository.
Create the repository if the registry requires it; retry a transient 5xx.
How to prevent it
Log in to the target registry with write scope in the same job.
Create ECR/registry repositories before the first push.
Wrap pushes in a bounded retry for transient registry 5xx.
Frequently asked questions
What causes ""failed to solve: failed to push""?
A push needs valid write credentials for the target registry. A missing docker login, a wrong token, or an expired one fails the push with 401/403.
How do I fix "failed to solve: failed to push"?
Log in to the exact registry with a token that can write the repository.
Can Latchkey fix this automatically?
Yes. Latchkey runs your GitHub Actions on managed runners that detect this failure, apply the fix, and retry the job automatically - self-healing is on by default.
