What would cause a cell phone to suddenly not be able to connect to WIFI or...

...or connect, but have a very VERY weak signal. So weak that it disconnects and says "Avoided poor internet signal".

This just started happening to me at work last week.

I can have my LG G3 and my LG G Pad side-by-side and the Gpad is connected to and receiving a strong signal yet my G3 can't even connect unless I'm in a certain spot in the facility and when connected, the signal is so weak that it usually disconnects.

THIS IS ONLY HAPPENING AT WORK. It connects and works fine on my home wifi and friend's homes wifi.

I thought maybe that they blocked my MAC address or something at work so I rooted and downloaded a MAC Address Spoofing app and it still wouldn't connect. I'd also think that if they blocked me, then I wouldn't be able to connect at all.


Any thoughts, input, advice?

Thanks