Fix it fast
Most likely: The registry was reached, but the exact repository and tag do not have a manifest, usually because the tag was never pushed or the image reference points at the wrong path.
1. Confirm this is your error
Error response from daemon: manifest for <image>:<tag> not found: manifest unknown: manifest unknown
manifest unknown: manifest unknown2. Check the cause
printf '%s\n' '<image:tag>'
docker manifest inspect <image:tag>
docker pull <image:tag>3. Apply the safe fix
# Use a tag that exists in that exact registry, namespace, and repository.
docker pull <registry>/<namespace>/<repository>:<existing-tag>
# If you own the image, build and push the missing tag intentionally.
docker build -t <registry>/<namespace>/<repository>:<tag> .
docker push <registry>/<namespace>/<repository>:<tag>4. Verify it works
docker manifest inspect <registry>/<namespace>/<repository>:<tag>
docker pull <registry>/<namespace>/<repository>:<tag>Don't use unsafe shortcuts
- Do not assume
latestexists, many repositories do not publish it. - Do not debug local Docker images for this error, the registry is saying the remote manifest is missing.
- Do not ignore registry host and namespace rewrites in CI or deployment templates.
What Docker Could Not Find for This Tag
Docker could not find the requested manifest for that image tag, which usually means the tag does not exist or the registry metadata is out of date.
Check the exact image name, tag, and registry
Print the exact image reference you are pulling, including the registry host and tag.
Check the registry UI or API and confirm that tag exists in that exact repository.
If a mirror or proxy registry is involved, compare the failing reference with a working environment to rule out the wrong upstream.
Confirm the exact image, tag, and registry
Confirm the full image reference first: registry host, namespace, repository, and tag, use the registry UI or API to verify the tag exists in that exact repository, and if CI or deployment code rewrites image names, print the final resolved image reference before docker pull and fix it there.
Why the Tag Does Not Resolve
The tag was never published in that repository.
The image reference points at the wrong registry host, namespace, or repository name.
A mirror or proxy registry is behind the source of truth and does not have that tag yet.
Verify the Tag Resolves Now
Run docker pull <image:tag> against the corrected image reference and confirm it succeeds, and run docker image inspect <image:tag> after the pull and confirm metadata is returned.
Avoid Version and Source Drift
To prevent this, use immutable tags or digests in deployment manifests instead of relying on mutable tags, and print the fully resolved image reference in CI so wrong registry or namespace rewrites are obvious.
How Docker looks up images, tags, and manifests
Docker asks the registry for the manifest behind one exact repository path and tag.
If that manifest does not exist at that path, the registry returns manifest unknown and the pull stops there.