F7 means the electronics have overheated.
What you can try is disconnect the mains supply and leave it 30 mins and then see if this corrects itself.
If not then its usually down to a faulty control board which would need to be replaced.
But if it does cure itself then see how it goes from there. If it happens again then check under the hob. If theres a drawer under the hob check this isn't full as it can block the ventilation around the hob and causes the F7 error code.