Blocked from responding?

It seems to happen randomly, I try to comment on a post and get this. This was on a random For Sale post.
Yes, I'm a member. yes I'm logged in.Attachment 209260

We're not allowed to reply to for sale posts. Read the rules at the top of the for sale section.

If you wish to follow up on a FS or WTB listing, you need to contact the poster via PM.

"The more you know!"

Thanks, I got it now.