USING GT ON PHONE?

I've been trying to log in to GT from my iPhone and I can't. Same for my iPad. On my iPhone, I can't even type in my username — I type, and no letters show up. The username box stays blank. I know people post from their phones. Everyone's always bragging about it (isn't that how things seem when you can't do those things?). Please tell me what I'm missing. I'm sure it's something super obvious. Yes, the phone is charged, the phone is on. I am in an internet browser. WiFi is connected. I'm almost there, people! Thank you!

ETA: I have a burner and am not attached to Facebook or Twitter, and I know my password/key because it always works on my home computer.