Tidbits, that's quite possible. Can you please positively confirm:
- Was it http://sila.altervista.org/ that you tested on T-Mobile? (this is my original issue)
- How about http://blog.viclone.com/ on T-Mobile? (this is an issue from somebody else's thread Error 504 Gateway Timeout)
Both give me "HTTP ERROR 504 Gateway Timeout" when accessing on T-Mobile data connection (no such error on WiFi). What's common between these two URLs is that they are on 5.0.0.0/8 networks.