Says IP is locked

[SonOfAGnome]

Hi,

I was trying to play with my son. I created this account (SonOfAGnome, I am ViciousGnome) for his use. I logged in on my computer. When he tried to log in on his computer with his separate account, it said:

"You are currently not allowed to login to the server because this IP has a temporary block on it. Please try again later."

He was able to log into a separate server, but that defeats the point: we want to play together. I read two boxing is not allowed, so I am guessing that because we are on the same router, and we have have the same ip, it won't let me get on the same server. I see my son every two weeks, and we would really like to play when we are together. Is there any way around this? Is it another problem I am missing? Any help would be appreciated. Thank you.