I can no longer connect to this forum with anything but my phone's browser. Neither of my work computers, nor my home laptop work. Neither does Tapatalk. I am confused and annoyed.
The forum address has been changed to start with https:. This ensures that communications to and from the forum are encrypted - in particular that your login remains secure.
In Tapatalk, remove the forum and then add it again; that will bring in the new address (starting https:) and it will work fine.
Because the forum is now https:, and (coincidentally) at the same time most servers have disabled SSLv3 because of the security breach known as Poodle, some browsers (webkit ones like Chrome and Opera in particular) will no longer open it when running on Windows XP because the more modern TLS is not sufficiently supported there. This will not change; if you are still running XP, it's time to move on.
You will likely see a warning sign in some browsers indicating that the secure forum pages are referencing insecure data from other sites. This is mainly because of external avatars - like mine! I plan to change my avi to an https: link, but maybe not everyone will.
When the forum was changed, restrictions on mixing secure and insecure links also broke the YouTube embedding (now fixed) and SoundCloud embedding (still broken - I have the fix, but there is a problem applying it that I am still working on). Twitter and Vimeo embedding was not affected.