Had the same problem here, a file name error ..the file has to be .X3G not .S3G ("files of type" drop down menu, save as .X3G)
Also I find more prints "gronk" via the SD card (perhaps because I've extended it?) I always use the PC now.
While I'm here, I have to say Geoff offers really good help.
Having said that, my FFCx runs a bit differently, most of my ABS runs the best at 222C, the hotbed at 102C with Kapton, mostly without rafts.
If it doesn't stick, I use the ABS glue (with MEK).
Also, on the bed leveling, I level it hot (~110C) with a sheet of plain paper, it may take a few go-rounds to get it right, but to be honest, I haven't leveled it in weeks, and yes I run it almost every day @0.22 resolution.
I snap off the prints with a chunk of oak stick & rubber mallet after the bed has cooled to ~80C (sounds crude, but it works), tap it at the base.
Just make sure you preheat the bed to allow it to stabilize before running a print.
Pics of some older & newer prints..and FFCx front panel mods (front lighted switch, plastic front cover, SD card extension)
My 2 cents anyway.
Cheers!
TD
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