A default install of mysql on debian would have bind-address set to 127.0.0.1. This is why you can’t accept remote connections to your mysql. In order to establish remote connections to mysql on debian servers, please comment the bind-address as shown below.

 42 language    = /usr/share/mysql/english
 43 skip-external-locking
 44 #
 45 # Instead of skip-networking the default is now to listen only on
 46 # localhost which is more compatible and is not less secure.
 47 #bind-address = 127.0.0.1
 48 #