This has also happened to me and when I rang I was told that this is not a known problem. Following a phone call a few days later to remind them that they had not responded to me, I have now got an email to tell me to fill in all names and dates of birth and death. I have not removed any from when it worked before so I don't see why (if, as they tell me they have not made any changes to their system) this should work now. They also inform me that I have to wait about 3 days before I will be able to see if this works. They also helpfully included a help line phone number which is not valid for my area.