First, make sure your system is up-to-date with "sudo pacman -Syu" Then you can try selecting new mirrors and "sudo pacman -Syy" to refresh your mirrorlist. It's good to have a main mirror, and a few backups.
Try checking the wiki: Mirrors - ArchWiki
Also check Mirrors status page: Mirror Status
Just as a side note, I couldn't find your mirror in the list of current mirrors, so there could be your problem.
If all else fails, I'd take it to the arch forums, but just a warning, you're going to have to provide a lot more information, packages you're trying to install, and possible the pacman jorunal error messages, etc...