Today there was a problem,
The site stopped working, no one could log into the interface, remote desktop onto the server failed / didnt work.....
The problem was someone doing a backup of the database server. They had remote desktopped into the system and started a backup, half way through an error message popped up and the system halted while SQL server waited for the response.
Every now and then something you do on MS SQL server throws up an erorr message. I'd advise to always act on it in a timely manner, as sometimes it keeps tables in the database locked whilst waiting fro a reply.
Keep focussed and dont do backups during critical times of the day 
If anyone knows why this happens, i'd love to know so do leave a comment.
Cheers!