HTC One M8 - Can't change APN settings - Any thoughts?

[AC Question]

Greetings, I have an unlocked HTC One M8 from Verizon. Because I'm not longer under contract with Verizon, I decided to try out this Wal-Mart family mobile (T-Mobile based). Great plan, affordable, etc. One problem I'm having is that I've installed the SIM card but I'm unable to get any data faster than "E" ("edge", I presume). T-mobile people have told me that I have to change the APN settings in my phone to those of the T-Mobile data network. However, I'm unable to add/change my device's APN settings. The sub-menu where I would change that is blank. There are no entries listed there. Can anyone shed some light on what I'm doing wrong?

 

[Rukbat]

Nothing - Verizon locks the APN (I think they unlock it you ask them to, but the phone has to be currently activated on Verizon for that). You could try an APN app - there are a lot of free ones, and it only has to work once.