From "blogger" today

Hello,

Thanks for letting us know about this. This weekend, a server issue was causing some problems with the word verification on blog comments. In some cases, this prevented comments from being created. The problem was fixed on Saturday evening (PST) so everything should now be working normally again.

If you continue to have trouble, please clear your browser's cache and cookies, and that should solve it. Thanks for your patience.

Sincerely,

Blogger Support