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))
About This Mac
System Report button
- Go to
Network -> 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.