Hi
F8 is a problem concerning the water level.
1/Check your filters arent blocked and that you arent using 3 or 4 in 1 tablets in conjunction with rinse aid as this will result in excess foaming.
2/A faulty recirculation pump or blockage within is a possibility.
3/Faulty water indicator also a factor.
Check (1) and if ok then its engineer time see below.