I’m having the same issue, and since I’m a lazy broad at times, I’m going to allow Mr. Scalzi to do the talking for me.
Originally posted on Whatever:
Over the last few days I’ve been getting people complaining that WordPress isn’t letting them comment because it says their e-mail address is associated with a WordPress account, and they need to sign in at WordPress, etc.
To be clear: I don’t know why that’s happening and it has nothing to do with how I’m running the site; on my end I have the same comment policy I’ve always had. This is possibly down to WordPress deciding to implement some internal dictum regarding people who have WordPress accounts, whether they remember that they do or not.