Probably not your IP address. Probably your phone’s operating system.
The hamfisted DDOS mitigation they put into place blocks almost everything but Windows. That includes Android, and probably IOS. (I don’t use IOS or MacOS, so I can’t testify to those firsthand.)
This thread by some very sharp Linux users figured it out. Unfortunately, I don’t think their workaround will be usable by most mobile device users.