3D Printer Stops Printing with “key:2571, Unknown exception” Error

Ender-3 V3 Printers Creality Ender-3 V3 Plus
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Hi everyone, I’m having an issue with my 3D printer.

During almost every printing operation, the printer suddenly stops and shows the following error:

“key:2571, Unknown exception”

When I resume the print, it works for a while but the same error appears again, causing the print to stop repeatedly. Any suggestions or troubleshooting steps would be greatly appreciated. Thank you!

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Feedback i found via Chatgpt:

Key: 2571, “Unknown exception” is a known issue on the Creality Ender-3 V3 series, including the Ender-3 V3 Plus. The interesting part is that it doesn’t necessarily mean a hardware failure.

The most likely causes are:

  1. G-code / character encoding problem

    • This is one of the recurring explanations for error 2571.

    • Special characters in the filename or G-code can sometimes trigger it.

    • There are reports of the same file printing successfully when transferred over Wi-Fi but failing from USB.

  2. Creality Print version

    • There are reports specifically connecting 2571/2000 errors with Creality Print 6.x.

    • One Ender-3 V3 user reported that reverting from Creality Print 6.0 to 5.1 resolved the problem.

  3. AI camera / AI detection

    • On the Ender-3 V3, users have reported that disabling AI detection eliminated recurring 2571 errors.

    • This is particularly worth testing if you have the Nebula camera connected.

What I would try first

If this is happening during a print, I’d do this in order:

1. Re-slice the model

  • Use the latest stable Creality Print version.

  • Give the file a very simple name, e.g.
    test_cube.gcode

  • Avoid spaces, accents, Chinese/Japanese characters, symbols, etc.

2. Try printing through Wi-Fi
If you normally copy the G-code to USB, send the same sliced file directly to the printer over Wi-Fi. There are reports where this avoided 2571 completely.

3. Disable AI detection
If you have the camera:

  • Disable AI detection

  • Restart the printer

  • Try the same print again

This is particularly interesting because the Ender-3 V3 community has specifically linked 2571 to AI detection.

4. Try a different slicer
As a diagnostic, slice the same model with OrcaSlicer and print it. If Orca works while Creality Print fails, that points strongly toward a G-code/slicer issue rather than the printer hardware.

5. Check firmware
Make sure the Ender-3 V3 Plus is running current firmware. I would not factory-reset it again as the first response; users have reported that a reset doesn’t necessarily resolve 2571.