As you can see there are some “bumps” on the first layer which makes it impossible to print. Does anyone know what the problem could be? I lubricated everything, changed the build plate and the material. I printed that same file without issues so i cant be the gcode file.
I guess there is stick-slip between filament and guide tube (internal or external).
To check, remove nozzle and tube from the print head and try to push a piece of filament through. If you feel some resistance, it is about time to renew the little teflon tube inside the hot end throat.
You may get a bit more life from it through carefully (and manually!) use of a 1.8mm drill - but not for long. The teflon tube degrades over time.
Same with the external bowden tube - filament must go through easily. If it doesn’t, it sticks every now and then until the transport drive manages to break it loose again - which causes the bumps.