Message in connect now when I print with MMU3 now functioning perfectly.  

RE: Message in connect now when I print with MMU3 now functioning perfectly.

I received this error on my Prusa XL. I eventually figured out it was due to a mismatch between the filament I loaded (PTEG) and the filament I sliced for (PLA). I reloaded the filament as PLA and the error resolved. 

RE: Message in connect now when I print with MMU3 now functioning perfectly.

I have that same error with my MK4S/MMU3 and in my case the same filament is loaded that I sliced for (all PETG).  The print request will just sit there until I click the 'print' button in PrusaConnect.  Any ideas would be greatly appreciated!

I tried to insert the screenshot below but what's shown is getting cut off for some reason.

RE: Message in connect now when I print with MMU3 now functioning perfectly.

UPDATE: The plot thickens....  I don't get the error when I send gcode for a single color print!  Must be something out of sync between what is assigned in Prusaslicer and what the MMU is expecting.  hmmmm.  

RE: Message in connect now when I print with MMU3 now functioning perfectly.

When you're sending MMU3 gcode, are you setting all 5 filaments to the same material that the slicer has configured?  I wonder if it's checking all 5 even though you're using less than 5...

RE: Message in connect now when I print with MMU3 now functioning perfectly.

The error only occurs when I request different colors in gcode.  In that case all 5 filaments are set to different colors.  When I send gcode that requests only 1 color, the other extruders are all set to other colors in Prusaslicer and I'm just selecting one of those for the part.  That doesn't produce an error.  Only when I have a part that calls for switching filaments does it give me the mapping error.  There's no discrepancy in the type of filament; all 5 filaments loaded to the MMU and in Prusaslicer are set to PETG (so, the source of this mapping error is not the same as what Corenth found above (which was a PLA/PETG mismatch)).  

RE: Message in connect now when I print with MMU3 now functioning perfectly.

Maybe it has something to do with that UI that pops up when you start the print from the printer itself - you know, where you can re-map the sliced extruders?  i.e. sliced extruder 1 maps to physical extruder 3, etc.  Does it save that mapping?  Maybe try printing from the UI once with multiple colours, and ensure the mapping is 1 to 1...

RE: Message in connect now when I print with MMU3 now functioning perfectly.

On your suggestion, I went to the printer UI and selected a multicolor file to print.  Everything looked fine in that color 1 and color 5 corresponded correctly so I clicked the 'filament' option and went through all 5 filaments, clicked the 'don't change' option and changed them to PETG.  They were already PETG but I just did it anyway and that solved the problem!  I can now send multicolor gcode files through Prusalink and they upload to the printer and just start printing without sitting there waiting for me to override the mapping error.  Thanks for the ideas!!!

RE: Message in connect now when I print with MMU3 now functioning perfectly.

Hmmm - seems like a bug to me.  Glad you worked it out!