I had the same problem and I just found the solution for me. I had to log onto my router (Lynksys connected to my Comcast modem) and disable IPv6. IPv6 uses longer IP addresses; LG K7 only supports the shorter addresses used in IPv4. So when I had both IPv6 and IPv4 enabled, my phone sometimes got sent the longer address, which caused it to not connect. Turning off IPv6 makes it work all the time now for me. Hope this helps.