Nexus "PUT ... 405 Method Not Allowed" deploying to a group/proxy in CI

Nexus group and proxy repositories are read-only aggregations. A PUT to them returns 405 Method Not Allowed. Deploys must target a hosted repository; use the group only for resolving dependencies.

What this error means

The deploy PUT fails with "status code: 405, reason phrase: Method Not Allowed" even though the same URL works fine for downloads and dependency resolution.

Nexus

[ERROR] Failed to deploy artifacts: Could not transfer artifact
com.example:app:jar:1.2.0 from/to nexus
(https://nexus.example.com/repository/maven-public/): status code: 405,
reason phrase: Method Not Allowed (405)

Common causes

Deploying to a group repository

maven-public (and similar group repos) merge several repos for reads only. They cannot accept writes, so PUT returns 405.

Deploying to a proxy repository

Proxy repos mirror an upstream and are read-only. Uploads to them are rejected with 405 the same way.

How to fix it

Deploy to a hosted repository

Resolve dependencies from the group repo (maven-public).
Deploy artifacts to a hosted repo (maven-releases or maven-snapshots).
Never point distributionManagement at a group or proxy URL.

pom.xml

<!-- reads from the group, writes to hosted -->
<repositories>
  <repository>
    <id>nexus</id>
    <url>https://nexus.example.com/repository/maven-public/</url>
  </repository>
</repositories>
<distributionManagement>
  <repository>
    <id>nexus</id>
    <url>https://nexus.example.com/repository/maven-releases/</url>
  </repository>
</distributionManagement>

Check the repository type in Nexus

In Nexus the repositories list shows Type = group / proxy / hosted. Only hosted accepts deploys.

How to prevent it

Use group repos for reads, hosted repos for writes.
Verify the target repository Type is hosted before deploying.
Keep resolve and deploy URLs distinct in your build config.