WiFi connecting problem in 5GHz networks
Just to make sure... Is visibility for 5G Wi-Fi network turned on? I.e., network is visible in the list of available networks, when you want to connect from any other device?

Also, try this:


Turn WPA2 only in the router settings.. 
Remove saved 5G Wi-Fi network on MBP and register again.


Just in case, make sure your MacBook supports 5G connectivity by:


Go to Apple menu (click  icon in the top left corner (menu bar))
Open About This Mac
Click System Report button
Go to Network -&gt; Wi-Fi section, find Supported PHY Modes and make sure that your adapter at a minimum supports 802.11g/n. 




And finally, this article may be very useful for running diagnostics on Wi-Fi connections.

Hope this helps at least find the path to fix.