I believe there maybe two reasons.

Firstly, there is a high possibility you do not have a static/stable internet connection. If you connect through a Ethernet port (The kind of cable that looks quite like a telephone) and your connection is shared this can happen. Shared connections operate in basis of time sharing so if there is a huge flow of data (For example, downloading a game or some 1080p full HD movies simultaneously)the passage gets overloaded and the system can't remember where to start again when access comes back to you. As a result problem in redirecting arises. This may cause this problem and also may show you a message has been sent several time even though you have pressed the send button only once. You can contact with your ISP for details.

Secondly, this site is going through some update or maybe some problem in the server is there. You can complain about this by clicking on the "contact us" link I think.