maven 出错，求大神指点一二，谢谢啦~ 400 请求报错 

[ERROR] Failed to execute goal on project shiro: Could not resolve dependencies for project shiro:shiro1.0-SNAPSHOT: Failed to collect dependencies at org.apache.shiro:shiro-core1.3.1: Failed to read artifact descriptor for org.apache.shiro:shiro-core1.3.1: Could not transfer artifact org.apache.shiro:shiro-core:pom:1.3.1 from/to nexus-osc (http://maven.oschina.net/content/groups/public/): Connect to maven.oschina.net:80 [maven.oschina.net/183.78.182.122] failed: Connection timed out: connect -> [Help 1]

[ERROR] 

[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.

[ERROR] Re-run Maven using the -X switch to enable full debug logging.

[ERROR] 

[ERROR] For more information about the errors and possible solutions, please read the following articles:

[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/DependencyResolutionException
maven启动就出现这个异常，然而度娘原因说的也是不明不白，求大神们告知下什么原因，怎么做。。