DON'T KEEP REFRESHING.
Here's an important piece of information: When the server says "Too busy", it means it's maxed it resources/bandwidth/etc, and isn't accepting any more connections. It does this in the hopes that it can fix whatever it overloading it, and bring the site up quickly.
REFRESHING/RELOADING THE PAGE DOES NOT HELP. AS A MATTER OF FACT, IT MAKES IT WORSE.
When the server has maxed its connections, trying to open new ones, really don't help.
So, next time you get this issue, don't sit there clicking the refresh/reload button.
Wait 20 minutes, come back and refresh ONCE. Not twice, not three times, not 20 times, BUT ONCE.