I switched from AT&T to Straight talk and here are my APN settings. Hope they work for you. These settings may not give you LTE speeds, but will get you 4G until you talk to the fools at Straight talk. If various APNs aren't working, check and recheck what you put in. I used MNVO instead of MVNO and got no data or MMS because of it.
Internet APN
APN: ATT.MVNO
Username: Leave Blank
Password: Leave Blank
Proxy Server (URL): Proxy.mvno.tracfone.com
Proxy port: 80
MMS APN
APN: ATT.MVNO
Username: Leave Blank
Password: Leave Blank
WAP gateway (URL): 66.209.11.33
WAP gateway port: 80
MMSC (URL): http://mmsc.cingular.com/
MMSC Port: 80
Maximum MMS Size: Leave Blank
Tried those settings along with using "tfdata" for the APN name along with a ton of other options and still nothing. I don't understand how there can be such a big variance on these things. It's almost like every phone has a unique setting to get it to work.
