Jenkins安装插件问题

        at java.lang.Thread.run(Unknown Source)
Caused by: java.net.UnknownHostException: build timeout
        at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
        at java.net.PlainSocketImpl.connect(Unknown Source)
        at java.net.Socket.connect(Unknown Source)
        at sun.net.NetworkClient.doConnect(Unknown Source)
        at sun.net.www.http.HttpClient.openServer(Unknown Source)
        at sun.net.www.http.HttpClient$1.run(Unknown Source)
        at sun.net.www.http.HttpClient$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at sun.net.www.http.HttpClient.privilegedOpenServer(Unknown Source)
        at sun.net.www.http.HttpClient.openServer(Unknown Source)
        at sun.net.www.http.HttpClient.<init>(Unknown Source)
        at sun.net.www.http.HttpClient.New(Unknown Source)
        at sun.net.www.http.HttpClient.New(Unknown Source)
        at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(Unknown Source)
        at sun.net.www.protocol.http.HttpURLConnection.plainConnect0(Unknown Source)
        at sun.net.www.protocol.http.HttpURLConnection.plainConnect(Unknown Source)
        at sun.net.www.protocol.http.HttpURLConnection.connect(Unknown Source)
        at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(Unknown Source)
        at sun.net.www.protocol.http.HttpURLConnection.getInputStream(Unknown Source)
        at hudson.model.DownloadService.loadJSON(DownloadService.java:167)
        at hudson.model.UpdateSite.updateDirectlyNow(UpdateSite.java:186)
        at hudson.PluginManager.doCheckUpdatesServer(PluginManager.java:1648)
        at java.lang.invoke.MethodHandle.invokeWithArguments(Unknown Source)
        at org.kohsuke.stapler.Function$MethodFunction.invoke(Function.java:396)
        ... 79 more