When the Maven Site plugin deploys a site to a repository, it needs to supply the appropriate deployment credentials. To configure this, you need to add credentials to your Maven Settings. Open up your ~/.m2/settings.xml and add the following server configuration to the servers element.
<settings> <servers> <server> <id>nexus</id> <username>deployment</username> <password>deployment123</password> </server> </servers> </settings>
Configuring Deployment Credentials for Site Deployment uses the default deployment user and the default deployment user password. You will need to configure the username and password to match the values expected by your repository manager.