why do i get you are not logged in & "You are not logged in. Please login and try again.?

[Annie]

This happens EVERY time I try to make a comment to ANYONE'S newspaper articles. I'm sure there are other sites, but off-hand can't think of them! There's a selection of Facebook, Yahoo, Twitter, disqus, etc. to login with. I've tried every one of them. I get "you are logging in with" & it gives my login name for that site, but still won't post my comment. This has been going on for a long time & I don't know what's going on. They seem to know who I am, but I keep getting the repeat of ""You are not logged in. Please login and try again". It's very frustrating! Thank you!
This happens with EVERY browser & I am logging in with the correct passwords! One person said to make sure Javascript is enabled. It IS in every browser! I appreciate the link Echo. Thank you! It will help in other matters, but I fail to see where it helps with this question!