FORUM Forums Software CLS2SIM Software Could not connect to X-Plane

Viewing 15 posts - 1 through 15 (of 16 total)
  • Author
  • #1134

    Just installed the latest version of CLS2Sim (4.20.0) and noticed something I haven’t seen before. Lots of error messages asking me if the X-Plane plugin has been installed (it has) but also telling me the connection was refused by the target machine.

    Maybe this is not a problem and simply a result of X-Plane not running but can’t remember I’ve seen it in the past when starting CLS2Sim before X-Plane.

    Here’s an example what it looked like

    Diego Bürgin

    You can safely ignore this.

    Its essentially just saying that it can’t connect to X-Plane because either X-Plane is not running or the plugin is not installed.
    We added this additional warning because we had folks who forgot/did not realize they need to install the X-Plane plugin.


    OK, just as I guessed then.

    Thanks for the confirmation though.


    I am seeing this message too, but X-Plane is running, and I installed the plugin.
    I am new to Cls2Sim and have not gotten it working yet. I can connect to the hardware, but have been consistently unable to connect to the simulator. The first time it attempts to connect, it says “a connection failed because the connection party did not properly respond in a period of time, or established connection failed because connection host failed to respond.” After that it switches to the “No connection could be made because the target machine actively refused it.”
    I used the plugin installer that came with CLS2Sim. The plugin appears to be in the right place per the Brunner YouTube video. CLS2Sim is running on the same machine as XPlane. I checked the Windows firewall, and both TCP and UDP appear to be open on all ports for CLS2Sim. I’m running on Windows 10 Pro with X-Plane 11.34r1 (build 113400 64-bit).
    Anyone have similar problems/ideas on how to solve them?
    Thanks in advance.


    One thing you could do if you didn’t already is checking log.txt in the X-Plane root folder and make sure the plugin was successfully loaded.



    In X-Plane11 the plane must be on the runway
    see also here



    I have the same problem. Before 11.34 everythinks ok, but now 🙁


    Hi Everyone,
    I have a similar problem. I’ve elected to post in this topic however I’m quite happy to start a new topic if the Moderators would prefer.
    I recently purchased the CLS-E NG Force Feedback Yoke and CLS-E Rudder. Initially I only connected the yoke but later the rudders via the CAN bus to the Yoke which is connected to the computer by the USB. I have read the documentation a number of times and believe the current installation has been done correctly. However, in troubleshooting I’ve made many changes, uninstalls and reinstalls. Currently I have the hardware connected as described. I wish to use the force feedback features and therefore have unistalled vJoy and instead using CLS2SIM. CLS2SIM sees all the hardware, roll, pitch, rudder pedals as force feedback devices and the brakes as analogue devices. However, CLS2SIM cannot seem to connect to X-Plane. (Yes it is on the runway.) The plugin is showing as active in X-Plane.
    X-Plane can see the pitch and roll control as well as at least some of the yoke buttons, even when CLS2SIM is NOT running. X-Plane has never seen the rudders or brakes.
    Win10 1903, CLS2SIM 4.23.3 Beta, X-Plane 11.36r2, XPlane10 Connector v6.2.3, vJoy (when installed).


    Update to my post above.
    I have now got CLS2SIM to connect to X-Plane after changing the IP on the Connections Settings page from localhost of to the actual IP of the machine. (I did that in the past but there were probably multiple other settings wrong!)
    I’ve started with Stefan’s Cessna 172 SP (CLSE-NG) from Profile Cloud.
    Thanks Stefan, nice job and a good starting point for me to experiment with the various settings.


    Hi all – after a couple of years of happy CLS-E operation I have faced precisely the same issues as above, ie “Is the plugin installed and enabled?” “No connection could be made because the target machine actively refused it” etc…

    After contacting Brunner directly some time ago, on their guidance I have done the following (on several occasions):

    · Uninstalled/ reinstalled Xplane
    · Downloaded latest Brunner software
    · Made sure Xplane was not running
    · Installed plugin
    · Checked the “Xplane 10 Connector” folder is in the right place
    · Started Xplane, then CLS software, on the runway
    · (and checked the plugin is working from the top menu within Xplane, but not while trying to activate the CLS software to avoid confusing it)

    …Then I checked the firewall settings (inc disabling the firewall) and entered the IP of the machine in the appropriate CLS software setup.

    As this issue surfaced during my first experience with Xplane directly (I had previously been operating Xplane and FSX Steam Edition via Flyinside) I also tried reverting to FSX Steam (via Flyinside), to find the same thing.

    …On both programmes it will connect to the hardware (and initialise), but not to the flight sim. In FSX it gives no reason for failure – it just goes off to restart every few seconds. FSX also has its plugin installed, BTW.

    I have also been through all the “prerequisites” menu several times.

    Running this on Windows 10 with a more than capable PC.



    Hi and an update to the above. Huge Thanks to Stefan Brunner who accessed my PC and found I had not used the IP (D’OH).

    The yoke now connects but judders / freezes. Brunner reports a third party programme is interfering, so I am off to source the solution through the X-Plane forums and remove other programmes in a “process of elimination”.


    And a further update Dec 9 – Pedals and throttle quadrant removed / uninstalled (to eliminate any potential conflicts) yet problem persists.

    Have discovered the yoke judders/freezes equally on X-Plane and FSX, while a substituted old Saitek X52 joystick/throttle combo work perfectly on both.

    All very mysterious!


    I have the same hardware set-up and some time ago I had some problems with the latest version of the CLS2sim software in combination with the latest WIN10 update. Sometimes after a WIN10 update, it resets the USB Power management: This computer is allowed to turn off this system ….
    My hardware is connected as follows:
    The CAN port of the yoke goes to the Rudder unit and the Rudder USB port goes to the USB port of my computer. (No USB hub)
    Are you sure that the X-Plane plugin has been installed correctly? So directly in the X-Plane 11 main directory?
    My X-Plane flightsim software version: 11.51.b3 and CLS2sim: 4.25.08.
    Regards and success

    You must be logged in to view attached files.

    Hi and huge thanks. I have checked the USB power mgment function and disabled the “allow Windows to turn off this USB for power saving” (or equivalent label) function and still no joy.

    I don’t have the rudder unit so the yoke USB output goes directly to a (blue) USB on the PC (similarly not through a hub). Brunner have logged on and remotely checked and re-installed the latest software and got the machine to talk to the yoke (thanks to the assignation above) but it keeps juddering/ freezing.

    X-Plane.exe has installed directly on the desktop and the Brunner plugin is showing as installed (again, Brunner checked everything remotely – excellent service).

    They are logging in again today and more shortly.


    Eureka! I have totally re-formatted the machine and installed a fresh copy of X-Plane plus the Brunner software (plus the graphics, etc) – at super-slow download speeds, yet only an overnight job.

    It works perfectly in 2-D.

    I am now downloading the Oculus software to take it to 3-D.

    I suspect, after around four years with the Brunner yoke, that one of the numerous automatic updates (Windows, graphics, etc) – plus FSX and other various installations – has created some sort of conflict, but will never know.

    The good news is now – problem solved!

    Huge Thanks to Stefan and his team and happy flying 🙂

Viewing 15 posts - 1 through 15 (of 16 total)
  • You must be logged in to reply to this topic.


In the BRUNNER forum you will find various discussions on different topics, such as setup, software use or general questions and concerns. 

Discuss with forum mebers, share your knowledge and experience or find answers to frequently asked questions that are answered directly by our Brunner team.

Go to BRUNNER Forum.

BRUNNER Helpdesk​

Do you have questions about a product you have already purchased or are you facing technical issues? 

Check our FAQs for quick help. The most common questions or problems are described there, including instructions.

If you are still stuck, please contact our BRUNNER Helpdesk. Open a ticket here.

BRUNNER Simulation​

BRUNNER is a leading manufacturer of flight simulation devices for the professional as well as the enthusiast sector.

Unlike other manufacturers, Brunner offers a realistic flight experience with the help of Force Feedback Technology and Control Loading System.

Discover the BRUNNER Shop.

BRUNNER Simulation

Industriestrasse 27
8335 Hittnau

+41 (0)44 953 10 10

© 2023 BRUNNER Elektronik AG | Privacy Policy |  Legal notice

🌴 Summer holiday 🌴

Please note: The BRUNNER team is out of office due to company holidays until August 5th.