Kobra II Max hotend won’t extrude or retract

My Kobra II max hotend won’t print anymore. It still gets hot but I can’t retract or extrude or manually remove the filament. I tried replacing the entire hotend with one from my older Kobra II Neo but whenever I select the extruded menu the machine crashes or reboots so I guess they are not compatible? Will replacing the hotend with a new one solve the issue or can it be a motherboard problem as well? Any advice is appreciated