I have a Kyocera c5020n with an occasional error "call service 7001: 0020988. It does clear if I power off/on.

If there is no another paper inside the machine, you can try to open & close the printer door & pull out any paper on any tray & load it again. at finally you can try to turn power off & on it again

Please provide me with error code

Related to the power supply or power supply pcb

may be bad cover interlock switch

You need a technician to update the FIRMWARE

Code: 6000
Contents: Broken heater lamp error
The temperature won't rise by 1°C/33.8
°F during warming up and the heater is
turned on for 5 seconds.
The temperature won't rise by 1°C/33.8
°F during printing and the heater is
turned on for 5 seconds with the duty
cycle more than 60%.

Causes:
- Defective fuser thermistor.
- Broken thermal cutout or heater lamp.
- Defective engine/high voltage PWB.

surprised you actually got doublesided... ok... in a situation like yours... I would update to the latest adobe reader... that has been known to give you issues with printing.... and if it continues call kyocera support... this sounds like an issue they would want to work on...

I’m happy to assist further over the phone at https://www.6ya.com/expert/norman_d2fa496dce30c65d

your best bet with this one.. is to call kyocera support... they might give you a simple answer.. where as a tech will charge you an arm and a leg...

I’m happy to assist further over the phone at https://www.6ya.com/expert/norman_d2fa496dce30c65d

power down unit and power on... if same error get a surge protector or power conditioner... plug unit into it and then power down and power up... if same error replace the memory card in the unit... if same error replace memory board...

I’m happy to assist further over the phone at https://www.6ya.com/expert/norman_d2fa496dce30c65d

main controller board is bad

I’m happy to assist further over the phone at https://www.6ya.com/expert/norman_d2fa496dce30c65d

remove from driver from control pannal>add remove program>
uninstall your printer driver & reinstall it i m shore its help u