After 48 hours Battle net servers seem to be up again. What happened though?
Blizzaed entertainment announced :
" Friday morning, we received several reports that players were having trouble accessing their characters. Specifically, some players were receiving the message "Player Not Found." We discovered the cause of the problem but, unfortunately, there was not a quick fix. Because this message was erroneous, if a player were to manually delete their character, this character would have been permanently removed from the Realm. In an effort to minimize unnecessary character loss caused by players attempting to troubleshoot the problem on their own, we decided the best option was to temporarily take down the Realms. Our programmers worked throughout the night, and we believe that the issues have been resolved."
Happy Gaming