Connection lost - constantly trying to reconect to server

So I am getting this bug where repetier server is constantly flashing a message that says it lost connection to server and that it is trying to reconect. 

I cannot do anything as it is constantly flashing. I've tryied to stop and start the server from windows menu. Also unisntalling and re-installing. Rebooting... No success.

I need help pls

Kind regards,


  • Please open the javascript console on your browser and check if there are any error messages. Especially if server tries to send non UTF-8 chars browser will stop connection. The main question is, if this is also your problem and if so what is causing it. What was the last thing you did before it started to not work?

    When you go in browser debug tools to network and select one of the websockets what are the last say 50 frames in communication? You can copy/paste them here.

    On which os is your server running?
  • I am using Chrome. I open the console by pressing Ctrl+Shift+I.

    In the console I get constantly the message toghether with the flashing error I put on my previous post.

    WebSocket connection to 'ws://localhost:3344/socket/?lang=es&sess=XnQWpayK%23QR5XJD1lYxchai%24%23srIe%5EnI' failed: Could not decode a text frame as UTF-8.
    r @ app-min.js?lang=es:28

    Does this help? I am not that much into software terms.

    Thanks a lot

  • I can not say if we found your reason, but we found that direct printing e.g. a stl file leads to this, especially binary stl files. So make sure to always upload a valid gcode not the 3d model. For next update we added a prefix test and some other tests to hopefully prevent uploading wrong file types here.

    Restarting the server would make that problem disappear if it is the source. Then delete the illegal file to not recreate the problem.
  • edited August 2021
    thanks a lot, but I am still having the issue. Restarting the server does not help. I even tried re-installing repetier server. Also, I deleted the stl file from my computer, if that what you meant. Still getting that flashing error. 

    I forgot to Say that I am on Windows 10
  • Ok windows 10 is a new information. In windows all infos are stored in C:\ProgramData\Repetier-Server so reinstalling does nothing, the error is in one of these files. If it is not too big, can you zip the folder and set it to me for analysis?
    Just drop a pm with download link (dropbox etc). 

    When you stop service rename it and start again it is working without all files/settings you added. That gets you going. You can also make a copy and start deleting parts until it works than you know from which file it comes. But I guess with the analysis of your zip I can also say what is going on.
  • Thanks a lot!. It is working fine now. As you said, the problem was in one of those folders. Exactly in C:\ProgramData\Repetier-Server\printer\(my printer name)\jobs

    The file I uploaded before having the issue was there. I deleted all the content and the problem is now gone.

    Thanks a lot again
  • I have the same issue but dont have a file printer in  C:\ProgramData\Repetier-Server\printer\(my printer name)\jobs
  • There are different reasons for this issue possible. You should check C:\ProgramData\Repetier-Server\logs\server.log to see where server stops. If this happened on 1.4.11 after uploading gcode to a project, please install 1.4.12 - that was a bug already fixed. Just run the normal installer since server is not running.
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