@Jateen 

Hi, do you mean it is able to connect internet by using other bands with BSNL SIM card but band 1 doesn't work?

When you set it to band 1 only, is there still any 4G signal? you could check the network type, band and signal strength when using band 1 only. If there is no signal and network type shows No Service, please insert the same SIM card into another 4G device to see if it works on band 1 or other bands. 

  @Jateen 

Hi, based on the screenshot, it seems that you are using Aritel SIM card with manually selected band 1 and internet status disconnected, could you please also check Advanced->Status page where we could check the network type, band and signal strength etc.?

In addition, how about the screenshot of Advanced->Status page when using BSNL SIM card with manually selected band 1? if it shows No Service, please insert the same SIM card into your smartphone, then check which network type and band it works on your smartphone.

For android phone, you could install LTE Discovery App or LTE Cell Info: Network Status App etc. to check the network type and band.
For iPhone, please type *3001#12345#* into the area you normally use to input a phone number and press call. You will enter Field Test mode, and you should see the Freq Band Indicator or EARFCN or UARFCN number.

  @Jateen 

Hi, based on the screenshot of mobile phone, even though it uses band 1, the signal strength is quite weak with RSRP -121dBm.

Please try to move the location of the MR200 to somewhere else with better BSNL signal such as near a window etc. to see if it will receive any signal from BSNL.

In addition, please also make sure the two external LTE antennas on the MR200 are still installed properly.