Connecting problem

Hello...
I can't log in to the game for two days.
Today and yesterday when I try to log in I wait to connect for like 15 seconds and then pop "Unable to connect. Please try later. If the problem persists, please contact technical support at (link for blizzard)".

What is problem and how solve this?

Btw I saw some players from Iran got this problem. But I'm from Serbia and the situation is the same..