T-Mobile APN?

I just got this thing and it's an amazing phone. I absolutely love it. But for the first time after having it for a few days, I decided to go on a lengthy drive only to realize that MY PHONE DOESN'T GET DATA!!!! I messed with the APN settings once I got back and got it to work with 3G, but I had no luck getting 4G LTE. I can get 4G LTE on my other phones, but was wondering if others have experience similar issues, and what have you guys done to resolve them.

Thanks