I have Intellij IDEA Community installed on a Linux box that needs to use an authenticated proxy to get to the Internet. I have a system-wide proxy on the box that works, and I have the proxy configured in ~/.m2/settings.xml. Maven correctly uses the proxy when I run try it from the command-line.
I have the same proxy configured within Intellij and it gives me the plugins listing correctly. But when I try to sync with the Maven repository withing Intellij I keep getting this:
[WARNING] Unable to get resource 'org.codehaus.mojo:hibernate3-maven-plugin:pom:2.2'
from repository restlet (http://maven.restlet.org): Authorization failed: Not
authorized by proxy.
I commented out the proxy config in my ~/.m2/settings.xml file, let the Intellij Proxy info alone, and then supplied the properties in Setting->Maven. Not sure why that worked (nor why the settings.xml wasn't working right) but it's working now.