Make sure to be connected to 2.4 GHz Wi-Fi:
May a hotspot help you.
Try to hold LEctenna™ in different directions and locations on your phone: The Wi-Fi might be polarized.
Increase the distance between your phone and the Wi-Fi Router:
A larger distance needs more energy.
Solder your LEctenna: Better contact improves efficiency.
Look up more info about LEctenna™: