Method 1 – Install Straight Talk’s APN Profile to get Your Data Connection working
You have to set the Access Point Names or APNs to get data and MMS services working. When you use AT&T, T-Mobile or Verizon service, this happens automatically. When you use Straight Talk you set it up yourself.
You can download a Carrier APN profile from the web to get you data connection working. Straight Talk has three different Carrier APN profiles on the Straight Talk web site. Download and try each of the Carrier APN profiles until you find one that works. The Carrier APN profile will only setup your internet or data connection, not MMS. Yes you read correctly, the Carrier APN profile does not set up MMS. The next section of this guide explains how to set up both data and MMS. I recommend you use the Carrier APN Profiles from Straight Talk to get your data service working first. After data works, try the corresponding MMS APN and other information needed for picture messaging.
1. From your Home Screen, Tap Safari. Type http://iapnupdateatt.straighttalk.com. Tap Go
4. Turn your iPhone off. Turn it back on. Make sure you turned the power off, not just put it to sleep.
5. After restart, Tap Settings->WiFi->Off