Cannot enable all OTA channels?

On “DVR—Local Over the Air Broadcast”
Hauppage HVR-955Q tuner - Shows 23 channels but only 11 enabled
Channels listed are not checked as enabled and I cannot get Plex to save them as checked.
I check them all, then click Save, but it will not update.
All 23 work great on Hauppage WinTV app.
Thanks,
TW

I think the problem is that Gracenote is not accurate with your zip / postal code. Epg is absolutely needed to enable the channel. Try different zip codes from your ota market. You may find one that will provide the Epg to all channels. If you receive channels from 2 different ota markets like me, try zip codes between both transmitters sites.

Figured it out. Thanks for the help.
BTW, is there a helpful user guide for Plex DVR function. I mean more than just showing the menus. Something that offers troubleshooting?
I know the forum works well but sometimes I hate to post to forums because I might have missed something stupid (like this).

I find lots of answers here:

https://support.plex.tv/hc/en-us