What Maven Could Not Find
Maven could not find an artifact in the configured repositories, and the missing result may be cached in the local repository.
Check the exact artifact name, version, and source
Force a remote re-check once with mvn -U -DskipTests package, fetch the artifact directly (replace coordinates) with mvn -q -Dartifact=groupId:artifactId:version dependency:get, and if the error mentions cached resolution, delete *.lastUpdated under ~/.m2/repository/<groupId path>/<artifactId>/ and retry.
Confirm the artifact version and source
Before you retry, confirm the exact name, version or tag, namespace, and index or registry this environment is supposed to use. Most fixes here are about pointing at the right thing.
Confirm the exact artifact coordinates Maven is trying to resolve (copy from the error output).
Verify the artifact exists in the expected repository (Central or your internal repository manager) and that you're using the correct repository URL.
If it is a snapshot, ensure a snapshot repository is configured and enabled for that build.
Force updates once to bypass cached misses:mvn -U -DskipTests package
Delete the artifact's cached miss (*.lastUpdated) under ~/.m2/repository/<groupId path>/<artifactId>/, then rerun the build.
If you are behind a mirror/proxy repository, confirm it is proxying the correct upstreams and that the artifact isn't blocked by policy.
Why It Was Not Found
Usually this comes down to the dependency coordinates are wrong (typo in groupId/artifactId/version), you are trying to resolve a snapshot from a release-only repository (or vice versa), the artifact is hosted in a private or non-default repository that is not configured for this build, or the artifact was recently published, but a cached not found result is preventing Maven from re-checking.
Prove the Source Resolves Correctly Now
Re-run mvn -DskipTests package and confirm Maven downloads the missing artifact, and confirm the artifact now exists in your local repo at ~/.m2/repository/<groupId path>/<artifactId>/<version>/.
Typical Output
[ERROR] Failure to find com.example:missing:jar:1.0.0 in https://repo.maven.apache.org/maven2 was cached in the local repository, resolution will not be reattempted until the update interval of central has elapsed or updates are forced
[ERROR] Could not find artifact com.example:missing:jar:1.0.0 in central (https://repo.maven.apache.org/maven2)How Maven looks up artifact versions
When Maven checks a repository and the artifact is not found, it records that result in the local repository using *.lastUpdated files. Until the repository update interval elapses (or updates are forced), Maven may skip re-checking remote repositories for that artifact.
Avoid Version and Source Drift
To prevent this, use a repository manager as the single source for upstream artifacts so all environments resolve consistently, avoid consuming unpublished snapshots across machines, publish snapshots/releases before depending on them, and when publishing a new version, expect some caching, use -U in CI if you depend on freshly published snapshots.
Docs and source code
github.com/apache/maven/blob/maven-3.9.6/maven-core/src/main/java/org/apache/maven/project/DefaultProjectDependenciesResolver.java
Resolver "not found" failures (including cached misses like "Failure to find ... was cached ...") bubble up into Maven via the underlying exception message (e.getMessage()). - GitHub
String msg = "Could not resolve dependencies for project " + project.getId() + ": " + e.getMessage();
DependencyResolutionException dex = new DependencyResolutionException(msg, e);
dex.setResult(e.getResult());
throw dex;