Gateway crashing issue & improving range

Using The Things Gateway and a Raspberry Pi Zero as my device.

When running the python script (instructions found here) on the raspi zero, I can see the traffic on my gateway and packets being received on my applications page until I am about 1 block away from the office. At this point, even when I come closer, packets won’t receive because the gateway has crashed:
1st LED: On - solid
2nd LED: Slowly flashing
3rd LED: On - solid
4th LED: Off

I have to reset the gateway to temporarily fix this issue every time I want to run another test.

My questions are, what does this light pattern mean and what are the common issues that can cause a gateway to crash like this, and how do I improve the range between the device and gateway without getting an external outdoor antenna? Ideally would like to improve range using the script, but any tweaks I currently make to parameters have no effect.

Any advice is greatly appreciated