Marlin 2.0 Error:checksum mismatch, Last Line: 38 (2 replies)

Hello experts

I used marlin 2.0 on my anycubic i3 mega since nearly 2 month.

Now i have a problem.

At my last prints i got sometimes a error.

Situation: The printer work for a few minutes and suddenly stopps. The Noozle didn't move in any ways. The extruder did nothing and the temperature still works.(Bed and Hotend). I only can press "restart" on the LCD. All other buttons doesn't work. But it was really mysterious...... I print a file and it works. After the job was finish, i choosed the SAME file again and suddenly the printer stopped after a few minutes.

I connect it with my PC and try it again. In the Terminal of the Repetier-Software i got this error:

Error:checksum mismatch, Last Line: 38

I checked the Thermistor of the bed. i fixed new cabels and checkted it again. it looks really good! so i don't believe to a broken wire.

So i clear my start code. Nothing happens....
My last idea was, to reinstall Cura again and don't use any backups. So i configured all settings new. Now the printer works.(it was for 1 week)

Yesterday i print a new gcode file(2hours), no problem.
I do it again and i got the error....

My startcode:

G28; Fahr zum Nullpunkt
M501
M420 S1
G92 E0; Setze den Extruder auf Null
G1 X5 Y5 Z0.28 F5000.0; Fahre an die Startposition X5 Y5 Z0.28
G1 X200 Y5 Z0.28 F1500.0 E15; Ziehe eine Linie nach X200
G92 E0; Setze den Extruder auf Null

My endcode

M104 S0 ; turn off extruder
M140 S0 ; turn off bed
M84 ; disable motors
M107
G91 ;relative positioning
G1 E-1 F300 ;retract the filament a bit before lifting the nozzle, to release some of the pressure
G1 Z+0.5 E-5 ;X-20 Y-20 F100 ;move Z up a bit and retract filament even more
G28 X0 ;Y0 ;move X/Y to min endstops, so the head is out of the way
G1 Y180 F2000
M84 ;steppers off
G90
;The-Final-
M300 S0 PNaN
M300 S2349 P63
M300 S0 P63
M300 S2217 P63
M300 S0 P63
M300 S2349 P63
M300 S0 P190
M300 S2217 P63
M300 S0 P190
M300 S987 P762
M300 S0 P508
M300 S2349 P63
M300 S0 P63
M300 S2217 P63
M300 S0 P63
M300 S2349 P508
M300 S1479 P508
M300 S0 P762
M300 S987 P63
M300 S0 P63
M300 S880 P63
M300 S0 P63
M300 S987 P63
M300 S880 P63
M300 S0 P190
M300 S1661 P63
M300 S0 P190
M300 S987 P63
M300 S880 P762
M300 S1661 P127
M300 S880 P63
M300 S0 P63
M300 S987 P762
M300 S880 P127
M300 S987 P127
M300 S2217 P254
M300 S987 P127
M300 S0 P127
M300 S880 P254
M300 S1661 P254
M300 S1479 P508
M300 S2349 P508
M300 S2217 P1016
M300 S2217 PNaN
M300 S2349 PNaN
M300 S2217 PNaN
M82 ;absolute extrusion mode
M104 S0

Before i used marlin 2.0, i worked with marlin 1.1.9

Thank you for your help.