There several reasons why an IP address is blocked (banned) and the list below are the likely reasons:
1) Entering the wrong username or password multiple times within 15 minutes when logging into the control panel, email, or a password protected area on the website.
2) Opening too many connections to the server at one time. For FTP, we recommend setting you FTP program to open no more than 2-3 connections at a time. For email, please set your email client to check email no more often than 5-10 minutes apart. If multiple computers are checking email, please stagger the times they are checking so they are not all trying to check email at the exact same time.
3) Several disconnects and reconnects in a short period of time may cause it.
4) We may in extreme situations manually block a range of IP addresses we see attacking the server.
If you cannot access the website, try accessing the domain(s) using www.megaproxy.com/freesurf/ or www.proxify.com/ which will not be blocked or access from another computer that is not on the same internet connection.
You can also try resetting your cable or dsl modem to get a new IP assigned to you.