Don't think it's an error. The Sunday Times have simply stopped allowing us to enter without buying the paper. We can still enter online when we buy the paper.
I contacted them yesterday as well, but no response so far!
Yes, you can usually enter on-line without having to pay a subscription. I've not entered it the last couple of weeks though.
I've had no trouble entering the competition recently until this week. I don't believe that there is any conspiracy to get us to pay to enter. I just think that the Sunday Times have an incompetent/lazy website manager. I have had correspondence with them over the years about this problem but it's just a waste of time talking to them.
I decided to have another look, before I logged off - and it's working!!! Hurrah!
I've never won it, and I only enter it if 1) I manage to work out the answers and 2) I like the prize!!! Good luck!
I e-mailed them earlier this morning & had a reply saying that they were experiencing difficulties with that part of the website. Now it's working & I can submit my answers.