APN on my at&t samsung galaxy s3 is not saving.

[fosterr334]

Hi,
I bought a galaxy s3 yesterday from a guy online. I am switching services from version to straight talk. I got the phone working with straight talk text and calls but when I try to enter the APN I click save and my APN never shows or saves. I was wondering if there is a solution to this problem?

Thanks,
Ryan

 

[fosterr334]

bump.
anyone have any advice ?