Invalid Username/Pass when connecting

[craig792]

Im running the JULT_repack V13, I can log into the server on the game fine. But someone outside of my local netwrok cant and says they are entering invalid username/pass. Ive checked the accounts table many times and is definatly the same as what weve been entering. However if i try logging into my friends account whos outside by local network, Inside the network i can connect. We both using the same realmlist and everything :s So what i dont understand is what could be stopping him logging in and giving the invalid username or password error? Sorry if its not clear ive tried my best to explain. Thanks In Advance
Regards
Craig