The linkcheck plugin does not use the NTLM proxy setting when trying to resolve an external link and fails. I get the following error: Checking link http://maven.apache.org/ Credentials cannot be used for NTLM authentication: org.apache.commons.httpclient.UsernamePasswordCredentials Received: [407] for http://maven.apache.org/ Received: [407] for http://maven.apache.org/ My proxy settings are ok with maven (can get dependencies from a remote repository), they are set in my user build.properties.