I paid to get a T-mobile galaxy s5 sim unlocked so that I could use it on At&t. I'm located in the US. I took the sim out of another non-functioning at&t galaxy s5 and put it in the t-mobile one. The sim unlock code was successful, and ever since then my calls and texts have been working just fine. However, the mobile data connection is not working and I cannot seem to ascertain why this may be. I have tried scanning for networks and automatic network selection through the settings --> more networks --> Network operators menu. Mobile data is enabled. I have a data plan through at&t. Wi-fi still works. Any ideas on how to fix this issue? Any help would be greatly appreciated. I was hoping that rooting the phone may help the issue, but I am new to this concept. As I have gathered, only certain models of s5 can be rooted as of yet, and I did not find a thread on rooting the G900T model for the s5's. Thanks for any help!