XBee S8 module data missing

I am from India.
Using Xbee S8 module (865/868LP).

The firmware version is: 8076
Channel Mask is: 0x1FF (863 to 865) even tried with 0x3FFFFFFF
Transmit power level: 25mV
Encryption: Enabled

When I did the throughput testing putting both the devices beside I got around 16 kbps throughput, but when I did the testing while keeping the devices 50 meters away with a minor obstacle like 1 wall then data packet missing started.

Why it is happening in just only 50 meters?


It is the obstructions that absorb some of the energy and cause the packets to be loss.