Need help with my Ultimaker 3 extended.
Error: Printcore in print head slot 1 nozzle size mismatch.
scroll down to
PRINTCORE 1 but don't click it. Look at the bottom of the display. Repeat for PRINTCORE 2
If one of your cores is programmed wrong (for example it's an AA 0.4 but the printer thinks it's an AA 0.8) then you can fix it by using the instructions here: