I am trying to install Bitbucket Server Notifier 1.20 ,but getting below error.

Installing Plugins/UpgradesInstalling Plugins/UpgradesPreparation Checking internet connectivityChecking update center connectivitySuccessBitbucket Server Notifier  Failure -java.net.SocketException: Connection reset at java.net.SocketInputStream.read(SocketInputStream.java:210) at java.net.SocketInputStream.read(SocketInputStream.java:141) at sun.security.ssl.InputRecord.readFully(InputRecord.java:465) at sun.security.ssl.InputRecord.readV3Record(InputRecord.java:593) at sun.security.ssl.InputRecord.read(InputRecord.java:532) at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:990) at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1388) at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1416) at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1400) at sun.net.www.protocol.https.HttpsClient.afterConnect(HttpsClient.java:559) at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:185) at sun.net.www.protocol.http.HttpURLConnection.followRedirect0(HttpURLConnection.java:2739) at sun.net.www.protocol.http.HttpURLConnection.followRedirect(HttpURLConnection.java:2651) at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1830) at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1498) at sun.net.www.protocol.http.HttpURLConnection.getHeaderField(HttpURLConnection.java:3061) at java.net.URLConnection.getHeaderFieldLong(URLConnection.java:629) at java.net.URLConnection.getContentLengthLong(URLConnection.java:501) at java.net.URLConnection.getContentLength(URLConnection.java:485) at sun.net.www.protocol.https.HttpsURLConnectionImpl.getContentLength(HttpsURLConnectionImpl.java:412) at hudson.model.UpdateCenter$UpdateCenterConfiguration.download(UpdateCenter.java:1264)Caused: java.net.SocketException: Connection reset at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:423) at sun.net.www.protocol.http.HttpURLConnection$10.run(HttpURLConnection.java:1950) at sun.net.www.protocol.http.HttpURLConnection$10.run(HttpURLConnection.java:1945) at java.security.AccessController.doPrivileged(Native Method) at sun.net.www.protocol.http.HttpURLConnection.getChainedException(HttpURLConnection.java:1944) at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1514) at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1498) at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:268) at hudson.model.UpdateCenter$UpdateCenterConfiguration.download(UpdateCenter.java:1280)Caused: java.io.IOException: Failed to load https://updates.jenkins.io/download/plugins/stashNotifier/1.20/stashNotifier.hpi to /var/jenkins_home/Jenkins/jenkins_test/plugins/stashNotifier.jpi.tmp at hudson.model.UpdateCenter$UpdateCenterConfiguration.download(UpdateCenter.java:1287)Caused: java.io.IOException: Failed to download from https://updates.jenkins.io/download/plugins/stashNotifier/1.20/stashNotifier.hpi (redirected to: https://get.jenkins.io/plugins/stashNotifier/1.20/stashNotifier.hpi) at hudson.model.UpdateCenter$UpdateCenterConfiguration.download(UpdateCenter.java:1321) at hudson.model.UpdateCenter$DownloadJob._run(UpdateCenter.java:1869) at hudson.model.UpdateCenter$InstallationJob._run(UpdateCenter.java:2147) at hudson.model.UpdateCenter$DownloadJob.run(UpdateCenter.java:1843) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at hudson.remoting.AtmostOneThreadExecutor$Worker.run(AtmostOneThreadExecutor.java:118) at java.lang.Thread.run(Thread.java:748)