Invalid IP address

This isn't about this site, but I just didn't want to clog up the General Discussion...

I tried to login to a website; entered my login and password, but then it just said "Invalid IP address". Do you have any idea why this happened? Or more importantly, how to overcome it?

Thanks in advance.

My guess would be that they log your IP address at sign up and think that your current one is too different to actually be you.

Moving to GD, as it's not related to this site.

That makes sense. Any way to convince them I'm still in the same place?!

E-mail the site owner?