Our server has been having a lot of rogue traffic/bots/hackers, which is causing trouble. We have deployed some additional security software but the flip side is that it can cause side effects. Example: when this software was activated, it blocked the ability to reply to topics/personal messages.
If you experience something where the site is not working like it did before, please copy the URL and create a post in the Help Forum with the link and the information on what you were doing and what didn't work.