You may have forgotten to add repository credential in you settings.xml, if it require authentication (that you fulfill wia your browser, even whithout knowing it):
Settings.xml :
<settings xmlns="http://maven.apache.org/SETTINGS/1.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0
http://maven.apache.org/xsd/settings-1.0.0.xsd">
...
<servers>
<server>
<id>corporate-nexus</id>
<username>login</username>
<password>password</password>
</server>
</servers>
...
</settings>
pom.xml
<repositories>
<repository>
<id>corporate-nexus</id>
<name>My Corporate repository</name>
<url>http://url.to.your.repo.corp</url>
</repository>
</repositories>
Be carefull, the id tags must have the same value.
Please add more information about your configuration if you want a more accurate answer
More information here : http://maven.apache.org/guides/mini/guide-multiple-repositories.html