Dns Issue?

So if I'm out and about, none of my hosting sites can connect. If I'm at home on my Wi-Fi  with Xfinity, there is no problem. As soon as I take the Wi-Fi off I lose my connection to my sites again. But there is no issue going to google, amazon, YouTube, etc. Could T-Mobile be blocking my sites or ip address. All this just sounds weird to me. Is anyone have the same issues? A fix?