I had the same issue for past few days. Fixed it eventually by manually removing the folding slot, and opening a new one.
Quick instructions on how to do that, in the advanced control go to configure -> slots, and remove your cpu slot, then add a new cpu slot (with preferences of your choice)
You will lose the WU in the old slot, I think (it will eventually timeout and be assigned to someone else). There may exist manual hacks involving quite likely deleting some or other cached file for better solution. Googling reveals similar problems happening earlier in past years, usually due to [email protected]
failing a core update somehow. No idea on the details.