I switched from T-Mobile to Straight Talk and after some frustration managed to get things working.
I ordered their ATT sim online from the Bring Your Own Phone section and a 1 month activation card. Everything showed up and I gave it a shot. Their online tool failed to allow me to port my number but they did it over the phone with no problem. AND I did not wait for customer service. Number was ported within a couple of hours.
I used the settings found on their website:
Which promptly failed to do anything. With various searching on the internet I found settings that mostly worked. Data, Voice , Text, MMS Send – but MMS receive failed. I would get the text notification but it would then fail to download and I would be looking at a blank message editing screen.
The short version is eventually called customer service told them what was going on and that the default APN settings didn’t work at all. They had me power down my phone while they configured my account on their end. I powered it back up and the settings I found on the internet stopped worked.
Deleted the old settings, named the new settings from their website (above) STRAIGHT_TALK and rebooted and then had everything working.
from my house with three bars:
Easy way to test MMS is to send yourself a MMS message.