I am trying to register for free hosting account but receive a strange message:

We detect that you are accessing our service through a proxy or attempting to register multiple times. We do not allow signups through proxy services or more than once per 24 hours. If you believe this is a mistake, please contact us on our forums.
I am located in Germany and use the Internet provider 1&1. I have a WiFi devices at home and use notebook to access the Net. What could be wrong with my configuration that your system recognize it "behind the proxy"?

Many thanks in advance!