R7800, Too many login attempts from your network

Yesterday I couldnt login to a game, it gave me the message that I had attempted too many login attempts, and I should wait before trying again. I thought it was something wrong with that particular website so I thought I could just wait it out. After several hours I noticed it wasn´t just that website. Now another gaming-website gave me a similiar message: "Too many failed login attempts from your network in a short amount of time. Please try again later." 

I tried restarting my modem and router with no success. It wasn´t until I "reset" the router I could login to those websites. What could have caused this issue?

This problem only occurred when using my own internet and not when I used 3G/4G