Why Preferred network selection not working on redmi 4(santoni)

[Android Central Question]

I am using single only VI sim card in first slot which support 4g,3g and GSM network but my phone showing signal only in 4g coverage zone otherwise no network in low 4g coverage but good 3g coverage.

I have used the same sim card with same APN settings in other phones and I can easily switch between preferred choice of network.

I have tried two methods so far
1. *#*#4636#*#*
2. Sim card and network settings option

I want my phone to prefer 3g since 4g coverage is almost negligible inside my house.

Help me out, if it's an OS issue, or should i root my phone, any application that can force the selection.

 

[belodion]

I have tried two methods so far
1. *#*#4636#*#*
2. Sim card and network settings option

What options do you see when you try those two methods?

https://forums.androidcentral.com/ask-question/409154-join-android-central-community.html