I just installed ubuntu 17.10. My wifi adapter had no signal and could not connect.
I was able to use: sudo modprobe -v rtl8723be ant_sel=2 to get a good signal, and all the wifi in the area are now visible.
When I try to connect to my router and use the key from the router which has not changed in 3 years, the adapter repeatedly asks for the key over and over again and never connects.
