Wifi Direct not working on LG-G4 I can turn on Wifi Direct on my LG G4, and I can connect to another phone. There is even a Wifi Direct icon on the notification bar. However, if I try to share something, I can not see it in the sharing options. 

Also, if I try to share the other way around, the G4 never receives the file, not even a confirmation popup comes up.

The other device is a Samsung S7.
It seems that manufacturers are now making  Wi-Fi direct to be compatible with same brands only.

Quoting a support chat concerning this issue, it was indeed the case, according to Samsung support:


  Wi-Fi direct only works between same manufacture phones. I am afraid
  it does not work with LG or any other brand.


One thing to note:


  Wi-Fi direct is a protocol, but you still have to have an app to use
  it. Samsung has S Beam and LG has SmartShare as well, but S beam only
  works with Samsung devices and SmartShare only works LG devices.


This is by design, and not LG G4 device specifically, you may still manage to connect but won't send any files like you noted, perhaps old smartphones still support cross brands functionality.

A proposed workaround is using 3rd party applications like Superbeam from playstore.

Reference


File sharing between phones