# Why do I have connection problems with Windows agents when I convert JENKINS\_URL to HTTPS?

**URL:** <https://community.jenkins.io/t/why-do-i-have-connection-problems-with-windows-agents-when-i-convert-jenkins-url-to-https/12309>\
**Category:** Ask a question\
**Tags:** windows\
**Created:** [February 7, 2024, 7:49am UTC](https://community.jenkins.io/t/why-do-i-have-connection-problems-with-windows-agents-when-i-convert-jenkins-url-to-https/12309 "2024-02-07T07:49:55Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![turkcankeskin](https://dub1.discourse-cdn.com/flex013/user_avatar/community.jenkins.io/turkcankeskin/32/3092_2.png) [@turkcankeskin](https://community.jenkins.io/u/turkcankeskin)\
**Post date:** [February 7, 2024, 7:49am UTC](https://community.jenkins.io/t/why-do-i-have-connection-problems-with-windows-agents-when-i-convert-jenkins-url-to-https/12309/1 "2024-02-07T07:49:55Z")

</div>

Hello,

I use Jenkins 2.426.3 LTS in my company. My Jenkins is installed on RHEL 8 server and is running on port 8080;

My Jenkins environments were previously serving my teammates via HTTP on port 80 with LoadBlancing. I decided to switch to HTTPS for security.

My LoadBlancing configs are as follows;

LoadBlancing:80 \>\> redirect LoadBlancing:443  
LoadBlancing:443 \>\> RHEL8-Jenkins-Server:8080  
LoadBlancing:10000 \>\> RHEL8-Jenkins-Server:10000 (TCP port for inbound agents)

When I converted my Jenkins environments to HTTPS on Loadblancing, I did not experience any problems with my agents or elsewhere; because my Jenkins\>System\>Configure - JENKINS\_URL= [HTTP://RHEL8-Jenkins-Server:8080](HTTP://RHEL8-Jenkins-Server:8080).

I decided to change the JENKINS\_URL to HTTPS. I need this. In some integrations, Jenkins APIs introduce themselves as the internal server, but my teammates do not have access to the internal server.

When I convert JENKINS\_URL to HTTPS in my Windows agents;

```auto
E:\Jenkins>C:\Java\11\bin\java.exe -Xms2048m -Xmx4096m -Xrs -jar slave.jar -jnlpUrl https://jenkins.xxx.com/computer/ci-windows-agent/jenkins-agent.jnlp -secret xxx
Jan 31, 2024 9:49:00 PM hudson.remoting.jnlp.Main createEngine
INFO: Setting up agent: ci-windows-agent
Jan 31, 2024 9:49:00 PM hudson.remoting.Engine startEngine
INFO: Using Remoting version: 3160.vd76b_9ddd10cc
Jan 31, 2024 9:49:00 PM hudson.remoting.Engine startEngine
WARNING: No Working Directory. Using the legacy JAR Cache location: 
Jan 31, 2024 9:49:00 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Locating server among [https://jenkins.xxx.com/]
Jan 31, 2024 9:49:00 PM org.jenkinsci.remoting.engine.JnlpAgentEndpointResolver resolve
INFO: Remoting server accepts the following protocols: [JNLP4-connect, Ping]
Jan 31, 2024 9:49:00 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Agent discovery successful
  Agent address: jenkins.xxx.com
  Agent port: 10000
  Identity: 61:02:37:45:a7:f7:82:3d:c2:6b:88:8c:3e:f1:ec:77
Jan 31, 2024 9:49:00 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Handshaking
Jan 31, 2024 9:49:00 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Connecting to jenkins.xxx.com:10000
Jan 31, 2024 9:49:00 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Trying protocol: JNLP4-connect
Jan 31, 2024 9:49:01 PM org.jenkinsci.remoting.protocol.impl.BIONetworkLayer$Reader run
INFO: Waiting for ProtocolStack to start.
Jan 31, 2024 9:49:11 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: Protocol JNLP4-connect encountered an unexpected exception
java.util.concurrent.ExecutionException: org.jenkinsci.remoting.protocol.impl.ConnectionRefusalException: Connection closed before acknowledgement sent
        at org.jenkinsci.remoting.util.SettableFuture.get(SettableFuture.java:223)
        at hudson.remoting.Engine.innerRun(Engine.java:822)
        at hudson.remoting.Engine.run(Engine.java:543)
Caused by: org.jenkinsci.remoting.protocol.impl.ConnectionRefusalException: Connection closed before acknowledgement sent
        at org.jenkinsci.remoting.protocol.impl.AckFilterLayer.onRecvClosed(AckFilterLayer.java:280)
        at org.jenkinsci.remoting.protocol.FilterLayer.abort(FilterLayer.java:165)
        at org.jenkinsci.remoting.protocol.impl.AckFilterLayer.lambda$start$0(AckFilterLayer.java:177)
        at org.jenkinsci.remoting.protocol.IOHub$DelayedRunnable.run(IOHub.java:958)
        at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
        at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
        at hudson.remoting.Engine$1.lambda$newThread$0(Engine.java:125)
        at java.base/java.lang.Thread.run(Thread.java:834)

Jan 31, 2024 9:49:11 PM hudson.remoting.jnlp.Main$CuiListener status
INFO: reconnect rejected, sleeping 10s:
java.lang.Exception: The server rejected the connection: None of the protocols were accepted
        at hudson.remoting.Engine.onConnectionRejected(Engine.java:901)
        at hudson.remoting.Engine.innerRun(Engine.java:848)
        at hudson.remoting.Engine.run(Engine.java:543)

```

I experienced the mistake.

When I did a little research, I saw that the traffic should proceed as LoadBlancing:10000 \>\> RHEL8-Jenkins-Server:10000 - TCP, but in my LoadBlancing, the traffic passes as TCP.

When I continued researching, I saw that Windows agents have a “Use WebSocket (JEP-222)” option.

My question ; “Why did I have connection problems with Windows agents when I changed JENKINS\_URL to HTTPS? and what is the difference between websocket and normal connection?”

---

<div class="post-metadata">

**Author:** ![Jana](https://avatars.discourse-cdn.com/v4/letter/j/258eb7/32.png) [@Jana](https://community.jenkins.io/u/Jana)\
**Post date:** [February 14, 2024, 5:35pm UTC](https://community.jenkins.io/t/why-do-i-have-connection-problems-with-windows-agents-when-i-convert-jenkins-url-to-https/12309/2 "2024-02-14T17:35:40Z")

</div>

> [@turkcankeskin](#):
>
> ```auto
> java.util.concurrent.ExecutionException: org.jenkinsci.remoting.protocol.impl.ConnectionRefusalException: Connection closed before acknowledgement sent
> 
> ```

@turkcankeskin check this

> [@Issue while connecting to windows agent from upgraded jenkins 2.387.1](https://community.jenkins.io/t/issue-while-connecting-to-windows-agent-from-upgraded-jenkins-2-387-1/6731):
>
> Hi, I am facing issue while making windows servers as an agent with jenkins. please see below details of it. Jenkins version - 2.387.1 JAVA - openjdk version “11.0.8” 2020-07-14 LTS When we are trying to connect a windows server using agent.jar with jenkins (Using JNLP-4), getting following Error - ERROR - Apr 04, 2023 8:36:54 PM hudson.remoting.jnlp.Main createEngine INFO: Setting up agent: IN\*\*\*\*\*\*\*\* Apr 04, 2023 8:36:54 PM hudson.remoting.Engine startEngine INFO: Using Remoting versi…