They are having some troubles with the IP address, but it should start working very soon.
I know it was down yesterday, but it's working fine for me. I usually use this website to check when a website is down or if it's something thats wrong with my comp:
http://www.isitdownrightnow.com/mangaupdates.com.html
Maybe try the instructions it gives for troubleshooting.
it's been 2 days since i can't access my mangaupdates?
why can't i access it?