Feb 20, 2017 7:49:19 AM hudson.model.UpdateCenter updateDefaultSite
WARNING: Upgrading Jenkins. Failed to update the default Update Site 'default'. Plugin upgrades may fail.
java.net.ConnectException: Connection refused
        at java.net.PlainSocketImpl.socketConnect(Native Method)
        at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:345)
        at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
        at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
        at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
        at java.net.Socket.connect(Socket.java:589)
        at sun.net.NetworkClient.doConnect(NetworkClient.java:175)
        at sun.net.www.http.HttpClient.openServer(HttpClient.java:432)
        at sun.net.www.http.HttpClient.openServer(HttpClient.java:527)
        at sun.net.www.http.HttpClient.<init>(HttpClient.java:211)
        at sun.net.www.http.HttpClient.New(HttpClient.java:308)
        at sun.net.www.http.HttpClient.New(HttpClient.java:326)
        at sun.net.www.protocol.http.HttpURLConnection.getNewHttpClient(HttpURLConnection.java:1168)
        at sun.net.www.protocol.http.HttpURLConnection.plainConnect0(HttpURLConnection.java:1104)
        at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:998)
        at sun.net.www.protocol.http.HttpURLConnection.connect(HttpURLConnection.java:932)
        at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1512)
        at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1440)
        at hudson.model.DownloadService.loadJSON(DownloadService.java:171)
        at hudson.model.UpdateSite.updateDirectlyNow(UpdateSite.java:190)
        at hudson.model.UpdateCenter.updateDefaultSite(UpdateCenter.java:2193)
        at jenkins.install.SetupWizard.init(SetupWizard.java:168)
        at jenkins.install.InstallState$3.initializeState(InstallState.java:105)
        at jenkins.model.Jenkins.setInstallState(Jenkins.java:1057)
        at jenkins.install.InstallUtil.proceedToNextStateFrom(InstallUtil.java:96)
        at jenkins.model.Jenkins.<init>(Jenkins.java:947)
        at hudson.model.Hudson.<init>(Hudson.java:85)
        at hudson.model.Hudson.<init>(Hudson.java:81)
        at hudson.WebAppMain$3.run(WebAppMain.java:231)