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My print didn't start: errors the printer reports

My print didn't start: errors the printer reports


When a print fails to start, SimplyPrint shows Printer failed to download or start with the message it got back: "Got the following error from the printer". That message comes from your printer, or from the software that connects it to SimplyPrint, so it tells you where to look. Find your message below: each section says what it means and what to do.


In this guide


"Failed to get AMS mapping table"

Your Bambu Lab printer couldn't match the file's filaments to its AMS slots. You may see it on a printer without an AMS too, and with files that always worked before.


  1. Update the SimplyPrint Client. If you still run the older SimplyPrint Bambu Lab Client, move to the new one: Migrating to the new SimplyPrint Client.
  2. Start the print again.


Check: the print starts.


"Printer rejected the file upload (429)"

The printer refused the upload and answered with code 429, which means "too many requests": the printer is busy and won't take another file right now. SimplyPrint shows the printer's answer as it got it. Elegoo's own software reads 429 from a Centauri Carbon 2 the same way, as "printer busy". You can see it on printers that the SimplyPrint Client sends files to over the network, such as Elegoo Centauri and Creality printers.


It usually means something else is talking to the printer at the same time: another upload that hasn't finished, or another app sending to it, such as ElegooSlicer, Elegoo's phone app or a second copy of the SimplyPrint Client.


  1. Close or stop anything else that sends files to the printer, and let any upload in progress finish.
  2. Wait a minute, then start the print again. The Client doesn't retry this error by itself.
  3. If it fails again, restart the printer.
  4. Update the SimplyPrint Client and the printer's firmware.


Check: the print starts. If it doesn't, send the Client's logs (see Still not starting).


"Print start rejected by the printer"

The file reached your Bambu Lab printer, but the printer refused to start it and gave no other reason. We've seen it after a printer firmware update, while the same file kept working on printers with the older firmware.


  1. Update the SimplyPrint Client, or move from the older SimplyPrint Bambu Lab Client to the new one: Migrating to the new SimplyPrint Client.
  2. Make sure the printer is in LAN-only mode with Developer Mode on. Current Bambu Lab firmware blocks starting prints from other software in Cloud mode: Bambu Lab: printer stopped working after firmware upgrade.
  3. Start the print again.


Check: the print starts.


Bambu Lab: no SD card or USB stick

SimplyPrint sends a file to a Bambu Lab printer by copying it onto the printer's storage, so every Bambu Lab printer needs a microSD card or USB stick inserted, depending on the model. Without one you see SD card or USB stick is not inserted, or Make sure you have an SD card or USB stick inserted.


  1. Insert a microSD card or USB stick into each printer, the kind your model uses.
  2. If the printer says the card is full (There is not enough space on the SD card or USB stick), delete old files from it on the printer's screen.
  3. Start the print again.


Check: the print starts.


File names with special characters

Very long file names, and names with brackets, braces or letters like ä, ö and ü, can make the transfer to the printer fail. On Bambu Lab printers this can even show up as an SD card error.


  1. Rename the file in SimplyPrint to something short with plain letters and numbers, such as test.
  2. Start it again.


Check: the print starts. If it does, rename your other files the same way.


"Error code: 83935248" on Bambu Lab

SimplyPrint shows a Bambu Lab error as Error code: followed by a number when it doesn't have a description for it. 83935248 is Bambu Lab's error 0500 C010: a microSD card error.


  1. Take the card out and put it back in.
  2. If that doesn't help, format the card in the printer, or try another card.
  3. Try a file with a short, plain name (see File names with special characters).


Check: the print starts.


Bambu Lab "cannot parse the file"

The printer received the file but can't read it. .gcode.3mf is the right format for a Bambu Lab printer, so the problem is usually this one file rather than the file type.


  1. Slice something simple, such as a cube, and start it. If that works, the first file is the problem.
  2. Slice the first file again, or with another slicer engine.
  3. To be sure SimplyPrint isn't the cause, download the file, copy it onto the printer's SD card or USB stick, and start it from the printer's screen. If it fails there too, the file is the problem.


Check: the re-sliced file starts.


Anycubic "cannot parse the file" or "Task abnormally ended"

The Anycubic printer received the file, but its firmware refused to start it. "The device cannot parse the file" is Anycubic's error 10115, and "Task abnormally ended" is error 10111. Anycubic firmware refuses some files made by other slicers: we've seen it with .gcode.3mf files on the Kobra X and Kobra S1, and OrcaSlicer has sometimes produced files the printer won't accept, for example on a Kobra 3 Max.


  1. Send a plain .gcode file, not a .gcode.3mf. The Cloud Slicer makes a plain .gcode for the Kobra X and Kobra S1 by itself. SimplyPrint no longer sends .gcode.3mf files to the Kobra X, Kobra S1 and Kobra S1 Max, so those printers show such files as "Printer doesn't support this file type".
  2. If you only have the .gcode.3mf, open it as a zip file and take out Metadata/plate_1.gcode. Upload that file and start it.
  3. If the printer still refuses a file from OrcaSlicer, export a plain .gcode from Anycubic Slicer Next and send that.


Check: the print starts. For which Anycubic printers connect and which files they take, see Anycubic Kobra X, Kobra S1 and Kobra 3: connecting and which file types work.


"File is empty"

The file arrived at the SimplyPrint Client with nothing in it, so the Client stopped before sending it to the printer. The older Bambu Lab Client showed this as "File was empty".


  1. Restart the SimplyPrint Client, or the computer it runs on.
  2. Start the print again.


Check: the print starts.


"Network Error" on a Klipper printer

On a Klipper printer, "Network Error" means Moonraker, on the printer, couldn't download the file from SimplyPrint. Moonraker downloads every file you send before it starts it.


  1. In Mainsail or Fluidd, download moonraker.log and search it for Failed to download file. The lines after it say why.
  2. Check that the printer still has a working internet connection.
  3. Large files can fail on printers with little memory, such as the Flashforge Adventurer 5M and 5M Pro, even when the same file uploads fine through Mainsail. With the Klipper setup, Moonraker downloads the whole file from SimplyPrint on the printer itself. The SimplyPrint Client downloads the file on another computer and then sends it to the printer over your network, the way Mainsail does. Connect through the Client instead: Connect your printers with the SimplyPrint Client.
    • On the printer's own Flashforge firmware, add it in the Client as a Flashforge printer (Adventurer 5M, 5M Pro, AD5X, Creator 5 and Creator 5 Pro).
    • On Klipper firmware (for example a modded Adventurer 5M), add it in the Client as Klipper (Moonraker).
    • Both connections are marked beta in the Client.


Check: the print starts.


Bambu Lab stuck on "Pending start"

SimplyPrint shows Pending start because that is the state the printer reports, and Cancel may do nothing while it is stuck.


  1. On the printer's screen, start any print from its SD card or USB stick, then stop it.
  2. If it happens again, update the printer's firmware: How to update Bambu Lab firmware in LAN-only mode.


Check: the printer shows as ready in SimplyPrint, and the next print starts.


Still not starting

Collect the logs from whatever connects the printer, then tell us the printer, the exact error and when it happened:


Updated on: 27/10/2026

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