Hi!
A couple of things come to mind.
First, try logging out of the archive, and then logging back in using the fields in the upper right corner. We have a known glitch that makes the center login fields work only when creating the new account and activating it. After that, they don't work.
Second, remember that passwords are case sensitive. If you used a capital when setting the password, you need to use a capital when logging in.
If neither of those help, then I suggest clearing your cache and cookies and logging in again. Sometimes you get a corrupted cookie string that can cause this issue. Just keep in mind that clearing your browsing history doesn't clear the cache. We have instructions here for most major browsers.