I know that several people have been having trouble leaving comments on Blogger for a while now. It finally happened to me. The solution is to make sure you uncheck the "stay signed in" box when you log in. That has worked for my husband and me.
On another note, I really love to read your comments and try to respond to each one. If you are a no reply, which means you haven't added your email to your profile, please add your email address to your comment so I can write back.