Hot End showing ERR

I have a filament jam in the hot end. After trying to clear the issue and reinstalling the heat break my display now shows err where the hot end temperature is supposed to be. What do I need to check now?

Hi @DWolfe In this case, could you pls try to measure the resistance of the nozzle thermistor to see if it is normal? Please note that it must be measured at normal room temperature. After the measurement it would be really helpful fi you could respond with a picture showing the thermistor resistance value for judgement.
(Test resistance method: multimeter gear rotated to 200KΩ gear, multimeter measuring pen placed on the thermistor line terminals. Reference picture below)