Slave getting disconnected frequently. Please check the log below.

Jun 19, 2017 9:21:32 AM hudson.remoting.jnlp.Main$CuiListener status
INFO: Handshaking
Jun 19, 2017 9:21:32 AM hudson.remoting.jnlp.Main$CuiListener status

Jun 19, 2017 9:21:32 AM hudson.remoting.jnlp.Main$CuiListener status
INFO: Trying protocol: JNLP4-connect
Jun 19, 2017 9:21:33 AM hudson.remoting.jnlp.Main$CuiListener status
INFO: Remote identity confirmed: fe:69:3c:a5:b3:d4:da:b1:4d:b4:d9:1b:0d:9a:1b:b4
Jun 19, 2017 9:21:33 AM hudson.remoting.jnlp.Main$CuiListener status
INFO: Connected
Jun 20, 2017 7:37:09 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Terminated
Jun 20, 2017 7:37:24 PM org.jenkinsci.remoting.engine.JnlpAgentEndpointResolver waitForReady
INFO: Failed to connect to the master. Will retry again
java.net.SocketTimeoutException: connect timed out
at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.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.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 org.jenkinsci.remoting.engine.JnlpAgentEndpointResolver.waitForReady(JnlpAgentEndpointResolver.java:312)
at hudson.remoting.Engine.innerRun(Engine.java:474)
at hudson.remoting.Engine.run(Engine.java:287)

Jun 20, 2017 7:37:39 PM org.jenkinsci.remoting.engine.JnlpAgentEndpointResolver waitForReady
INFO: Failed to connect to the master. Will retry again
java.net.SocketTimeoutException: connect timed out
at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.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.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 org.jenkinsci.remoting.engine.JnlpAgentEndpointResolver.waitForReady(JnlpAgentEndpointResolver.java:312)
at hudson.remoting.Engine.innerRun(Engine.java:474)
at hudson.remoting.Engine.run(Engine.java:287)

Jun 20, 2017 7:37:54 PM org.jenkinsci.remoting.engine.JnlpAgentEndpointResolver waitForReady
INFO: Failed to connect to the master. Will retry again
java.net.SocketTimeoutException: connect timed out
at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.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.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 org.jenkinsci.remoting.engine.JnlpAgentEndpointResolver.waitForReady(JnlpAgentEndpointResolver.java:312)
at hudson.remoting.Engine.innerRun(Engine.java:474)
at hudson.remoting.Engine.run(Engine.java:287)

Jun 20, 2017 7:38:09 PM org.jenkinsci.remoting.engine.JnlpAgentEndpointResolver waitForReady
INFO: Failed to connect to the master. Will retry again
java.net.SocketTimeoutException: connect timed out
at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.doConnect(Unknown Source)
at java.net.AbstractPlainSocketImpl.connectToAddress(Unknown Source)
at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.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.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 org.jenkinsci.remoting.engine.JnlpAgentEndpointResolver.waitForReady(JnlpAgentEndpointResolver.java:312)
at hudson.remoting.Engine.innerRun(Engine.java:474)
at hudson.remoting.Engine.run(Engine.java:287)

Jun 20, 2017 7:38:19 PM org.jenkinsci.remoting.engine.JnlpAgentEndpointResolver resolve
INFO: Remoting server accepts the following protocols: [JNLP4-connect, JNLP-connect, Ping, JNLP2-connect]
Jun 20, 2017 7:38:19 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Agent discovery successful

Agent port: 58461
Identity: fe:69:3c:a5:b3:d4:da:b1:4d:b4:d9:1b:0d:9a:1b:b4
Jun 20, 2017 7:38:19 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Handshaking
Jun 20, 2017 7:38:19 PM hudson.remoting.jnlp.Main$CuiListener status

Jun 20, 2017 7:38:19 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Trying protocol: JNLP4-connect
Jun 20, 2017 7:38:20 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Remote identity confirmed: fe:69:3c:a5:b3:d4:da:b1:4d:b4:d9:1b:0d:9a:1b:b4
Jun 20, 2017 7:38:20 PM org.jenkinsci.remoting.protocol.impl.ConnectionHeadersFilterLayer onRecv
INFO: [JNLP4-connect connection to ] Local headers refused by remote: Literature-Testing-Slave2 is already connected to this master. Rejecting this connection.
Jun 20, 2017 7:38:20 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Protocol JNLP4-connect encountered an unexpected exception
java.util.concurrent.ExecutionException: org.jenkinsci.remoting.protocol.impl.ConnectionRefusalException: Literature-Testing-Slave2 is already connected to this master. Rejecting this connection.
at org.jenkinsci.remoting.util.SettableFuture.get(SettableFuture.java:223)
at hudson.remoting.Engine.innerRun(Engine.java:385)
at hudson.remoting.Engine.run(Engine.java:287)
Caused by: org.jenkinsci.remoting.protocol.impl.ConnectionRefusalException: Literature-Testing-Slave2 is already connected to this master. Rejecting this connection.
at org.jenkinsci.remoting.protocol.impl.ConnectionHeadersFilterLayer.newAbortCause(ConnectionHeadersFilterLayer.java:375)
at org.jenkinsci.remoting.protocol.impl.ConnectionHeadersFilterLayer.onRecvClosed(ConnectionHeadersFilterLayer.java:432)
at org.jenkinsci.remoting.protocol.ProtocolStack$Ptr.onRecvClosed(ProtocolStack.java:832)
at org.jenkinsci.remoting.protocol.FilterLayer.onRecvClosed(FilterLayer.java:287)
at org.jenkinsci.remoting.protocol.impl.SSLEngineFilterLayer.onRecvClosed(SSLEngineFilterLayer.java:172)
at org.jenkinsci.remoting.protocol.ProtocolStack$Ptr.onRecvClosed(ProtocolStack.java:832)
at org.jenkinsci.remoting.protocol.NetworkLayer.onRecvClosed(NetworkLayer.java:154)
at org.jenkinsci.remoting.protocol.impl.BIONetworkLayer.access$1500(BIONetworkLayer.java:48)
at org.jenkinsci.remoting.protocol.impl.BIONetworkLayer$Reader.run(BIONetworkLayer.java:247)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at hudson.remoting.Engine$1$1.run(Engine.java:94)
at java.lang.Thread.run(Unknown Source)
Suppressed: java.nio.channels.ClosedChannelException
... 7 more

Jun 20, 2017 7:38:20 PM hudson.remoting.jnlp.Main$CuiListener status

Jun 20, 2017 7:38:20 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Server reports protocol JNLP4-plaintext not supported, skipping
Jun 20, 2017 7:38:20 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Server reports protocol JNLP3-connect not supported, skipping
Jun 20, 2017 7:38:20 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Trying protocol: JNLP2-connect
Jun 20, 2017 7:38:20 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Protocol JNLP2-connect encountered an unexpected exception
java.util.concurrent.ExecutionException: org.jenkinsci.remoting.protocol.impl.ConnectionRefusalException: Server didn't accept the handshake:
at java.util.concurrent.FutureTask.report(Unknown Source)
at java.util.concurrent.FutureTask.get(Unknown Source)
at hudson.remoting.Engine.innerRun(Engine.java:385)
at hudson.remoting.Engine.run(Engine.java:287)
Caused by: org.jenkinsci.remoting.protocol.impl.ConnectionRefusalException: Server didn't accept the handshake:
at org.jenkinsci.remoting.engine.JnlpProtocol2Handler.sendHandshake(JnlpProtocol2Handler.java:134)
at org.jenkinsci.remoting.engine.LegacyJnlpProtocolHandler$2.call(LegacyJnlpProtocolHandler.java:162)
at org.jenkinsci.remoting.engine.LegacyJnlpProtocolHandler$2.call(LegacyJnlpProtocolHandler.java:158)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at hudson.remoting.Engine$1$1.run(Engine.java:94)
at java.lang.Thread.run(Unknown Source)

Jun 20, 2017 7:38:20 PM hudson.remoting.jnlp.Main$CuiListener status

Jun 20, 2017 7:38:20 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Trying protocol: JNLP-connect
Jun 20, 2017 7:38:20 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Protocol JNLP-connect encountered an unexpected exception
java.util.concurrent.ExecutionException: org.jenkinsci.remoting.protocol.impl.ConnectionRefusalException: Server didn't accept the handshake:
at java.util.concurrent.FutureTask.report(Unknown Source)
at java.util.concurrent.FutureTask.get(Unknown Source)
at hudson.remoting.Engine.innerRun(Engine.java:385)
at hudson.remoting.Engine.run(Engine.java:287)
Caused by: org.jenkinsci.remoting.protocol.impl.ConnectionRefusalException: Server didn't accept the handshake:
at org.jenkinsci.remoting.engine.JnlpProtocol1Handler.sendHandshake(JnlpProtocol1Handler.java:121)
at org.jenkinsci.remoting.engine.LegacyJnlpProtocolHandler$2.call(LegacyJnlpProtocolHandler.java:162)
at org.jenkinsci.remoting.engine.LegacyJnlpProtocolHandler$2.call(LegacyJnlpProtocolHandler.java:158)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at hudson.remoting.Engine$1$1.run(Engine.java:94)
at java.lang.Thread.run(Unknown Source)

Jun 20, 2017 7:38:20 PM hudson.remoting.jnlp.Main$CuiListener error
SEVERE: The server rejected the connection: None of the protocols were accepted
java.lang.Exception: The server rejected the connection: None of the protocols were accepted
at hudson.remoting.Engine.onConnectionRejected(Engine.java:484)
at hudson.remoting.Engine.innerRun(Engine.java:448)
at hudson.remoting.Engine.run(Engine.java:287)

C:\Users\jenkins\Downloads>java.io.IOException: Backing channel 'JNLP4-connect connection from ""' is disconnected.