Everest cruise control malfunction

I had a similar issue with my old Mitsubishi. Before diving too deep, did you check the pedal switch? Sometimes those get sticky or break and cause the cruise control to disengage. Also, did you verify the throttle position sensor?

Which pedal switch are you referring to - the brake or the clutch pedal switch? Or both? And how would I verify the throttle position sensor?

Both switches, but the brake pedal switch is more likely. If the car thinks you're braking, it will disable cruise control. The throttle position sensor is harder to check without proper tools. If the switches are OK, I would suggest a trusted workshop.

I took it to a workshop today, and it turned out to be a faulty cable connection, as suspected. Repair cost was 95€. All sorted.