On mobile message looks like this.

We only allow 2 accounts being used on the same network. By network, we mean when two devices are using the same Wi-Fi. When in a short period of time the 3rd account connects using the same network, the game blocks it from login by showing the message "using more than 2 accounts is prohibited". Do not worry, you'll be able to log in again within the next 24 hours. It's an automatic action, we can't make an exception for your specific account.