Have you tried different colors of the filament or use the same filament each time it failed?
I know they designed a new Heat block to fix issues like these (as ZGLASS has this issue) and we are awaiting the release of the new block for purchase.
I had the same problem with warm gray ABS yesterday. 4 failed prints, because extruder stoped pushing the material through nozzle.
Disasemble the extruder stepper motor, clean the gear. There is a small bearing opposite of the gear. Clean this bearing and use PTFE grease on it. Push the stepper motor towards the bearing (to the right) when tightening 4 screws.
Problem solved. Overnight print with the same material.