What Broke in the Dependency Graph
Maven could not resolve one or more project dependencies, usually because of missing artifacts, bad repository settings, or network access problems.
This is Maven refusing to continue with a dependency graph that does not make sense. The important detail is which versions or peer requirements disagree, not just the final error code.
Repair the dependency graph
Try to repair the version graph instead of forcing past it. A successful command with mismatched dependencies is usually just a slower failure later.
Identify the first missing/failed artifact in the output (look for Could not find artifact ... or Could not transfer artifact ...).
Confirm the dependency coordinates in pom.xml are correct (exact groupId/artifactId/version, and snapshot vs release).
Confirm the artifact exists in the intended repository (Maven Central or your internal repository manager) with the exact coordinates.
If the artifact is private, ensure the correct repository is configured and credentials are provided via ~/.m2/settings.xml (match <server><id>...</id></server> to the repository <id>).
If the error mentions cached misses or you recently published the artifact, force updates once:mvn -U -DskipTests package
Clear the specific cached failure:delete the affected artifact directory and any *.lastUpdated files under ~/.m2/repository/<groupId path>/<artifactId>/, then retry.
If this only fails on certain networks, fix proxy/TLS access first (check settings.xml proxies and corporate certificate trust), then retry.
If needed, re-run with debug to see the exact repository URLs Maven is using:mvn -X -DskipTests package
Why Resolution Broke
This tends to show up after partial upgrades, lockfile drift, or introducing a package whose declared compatibility does not match the rest of the tree.
The dependency coordinates are wrong (groupId / artifactId / version / classifier / packaging). The artifact exists, but it is in a repository Maven is not configured to use (missing repository, mirror, or profile). A corporate proxy/VPN/firewall blocks Maven from reaching the repository host.
The repository requires authentication, but no matching <server> credentials are configured in ~/.m2/settings.xml.
A previous not found or transfer failure was cached in .m2 (*.lastUpdated), so Maven is not retrying yet.
Prove the Graph Is Clean Again
Re-run mvn -DskipTests package and confirm dependency resolution completes without errors, and run mvn -q -DskipTests dependency:tree and confirm the previously failing artifact resolves.
Manual dependency resolution checklist
If the main log is noisy or truncated, these checks let you isolate the failing layer directly and confirm whether you are dealing with configuration, access, trust, or local environment state.
Run with stack traces to find the first Caused by line: mvn -e -DskipTests package.
Print effective settings (mirrors, proxies, servers):mvn -q help:effective-settings
Force Maven to re-check remote repos once:mvn -U -DskipTests package
Inspect the dependency chain that pulled in the failing artifact:mvn -q -DskipTests dependency:tree
Try fetching the failing artifact directly (replace coordinates):mvn -q -Dartifact=groupId:artifactId:version dependency:get
Print the local repository path Maven is using:mvn -q help:evaluate -Dexpression=settings.localRepository -DforceStdout
Examples
[ERROR] Failed to execute goal on project app: Could not resolve dependencies for project com.example:app:jar:1.0.0: Failed to collect dependencies at org.example:lib:jar:1.2.3: Failed to read artifact descriptor for org.example:lib:jar:1.2.3
[ERROR] Could not resolve dependencies for project com.example:app:jar:1.0.0: The following artifacts could not be resolved: org.example:lib:jar:1.2.3: Could not find artifact org.example:lib:jar:1.2.3 in central (https://repo.maven.apache.org/maven2)How Maven resolves dependencies
This is the part worth understanding if the quick fix did not hold. It explains what Maven is trying to do at the moment the error appears.
Maven reads your pom.xml, builds a dependency graph, and computes the full transitive set of artifacts.
Artifacts (POMs, JARs, metadata) are downloaded from configured repositories (and mirrors) into the local repository (default:~/.m2/repository).
If any artifact is missing, blocked, unauthorized, or fails to download, the dependency resolution phase fails and the build stops.
Keep the Dependency Graph Healthy
To prevent this, use a repository manager (RepoFlow/Nexus/Artifactory) as a single upstream proxy for Maven Central and private repositories, publish artifacts (including parent POMs) before consuming them in CI, pin dependency versions to keep builds repeatable across environments, and standardize settings.xml (mirrors/proxies/servers) for developer machines and CI runners.
Docs and source code
github.com/apache/maven/blob/maven-3.9.6/maven-core/src/main/java/org/apache/maven/project/DefaultProjectDependenciesResolver.java
Maven constructs the top-level "Could not resolve dependencies for project ..." message while rethrowing dependency resolution failures. - 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;