Why am I unable to use 4G LTE on my smasung galaxy S6?

[Osdiv]

I have selected 4G/3G/2G in my network mode and it always shows 4G on my network bar even when I select 3G only on my network mode. My mobile network carrier is on the LTE band 3. And also when I dail *#*#4636#*#* and select LTE only to force the network to use LTE, the network goes off.

 

[B. Diddy]

Welcome to Android Central! What's the exact model number of the phone, and what carrier are you using, in which country? And just to clarify, do you mean that the phone always shows 3G on the status bar, even when you select 4G only? That's what your thread title implies, but you say the reverse in the body of the post.