Error sending form and log-in issues

I have been having issues with sending form which shows up as "Error sending form". In addition, my log-out button and log-in system don't work  (the log-in system worked before and I created accounts from bravo vision but now it does not work at all and leads me to the next page). The word "Log-in" also does not show up in bravo vision though the tags are exactly the same as the sign-up one. What could the problem be? Thanks in advance for helping me out!