J/k, check and see which modem/baseband is installed on your phone.
#1. Goto "Settings"
#2. Click "About Device"
#3. Baseband version should end with "ANE6"
If it reads otherwise, then you need to install the latest modem/firmware, found here sammobile.com , or by looking in the android development section of these forums.
Let me know what your device says to better diagnose the issue.
Sent from my SM-G900T using Tapatalk