I had no issues with activation and setup plus connecting to my router at 5.8ghz. After a factory reset, I'm no longer able to connect to my router using wifi 5.8ghz. 2.4ghz is fine and I can see all the networks. 5.8ghz networks are not shown. If I try adding the 5.8ghz network manually, I still not able to connect. I looked everywhere for this and found nothing. I hoping for a solution if anyone here or DJI has one.

MINE WILL NOT CONNECT EITHER ACTUALLY IT NEVERS HAS TO THE 5.8, THIS MUST BE A HARDWARE ISSUE?

I just did the same thing and can no longer connect via 5.8ghz.   Did you find a resolution to this?

So I managed to ‘fix’ this, but I’m not sure which step in particular did it.   

1] Turn on high accuracy gps services
2] Go outside and start up remote, crystal sky, and drone (make sure you have a gimbal attached for crystal sky).   Start the app.
3] wait until you have a crystal sky gps fix (the blue dot in the map showing where you are)
4] turn wifi off in settings, and then back on - your 5.8ghz networks should be selectable again.

My theory is that the 5.8 ghz georestriction service needs to get a location from the gps, and it probably only does this opportunistically and sparingly when other apps are querying the GPS.  The country code entry on very first startup may subvert this initially. It also doesn’t seem to be tied to changing the location shown in the automatic time zone detection, which makes sense to me.   All this is just  a guess, though.  If I bust 5.8ghz again, I’ll narrow it down some more

The solution may be as simple as go outside with some app that heavily uses the gps, and wait.

[Edit]I reconfirmed that this works after having to do another erase settings while trying to track down a different crystal sky issue.

I also suspect doing a full factory reset would have likely fixed the issue as well, but this far I’ve found no procedure for doing one.   Erasing the settings and reinstalling the firmware don’t seem to be as comprehensive as a factory reset would be.   (Particularly bringing up the Eula’s and country select screen)