DSL CONNECTION ALWAYS DISCONNECTED

ELO guys plzz.. help me to my dsl connection because always disconnected after 10seconds and i’m using zyxel p-600 series.. I’m trying to configure it to another computer and laptops but then its the same problem with my computer but not all computer and laptops are disconnected there are some computer are get connected.. how should I do? its been 1 month this problem is not solve the problem.