My issue was never that I couldn't reload the channels. The issue is that many of the channels that they deleted were pay channels and I had to spend up to an hour re-signing into them. I finally managed to solve the problem by switching to an Apple TV4K.
Re: Can no longer get antenna channels - no channel available
Gee Roku. I gave you all kinds of props earlier today. My bad. First no Channel guide. It came back with instructions from Danny except for local channels. I reloaded channels everything was good. Left watching local show. Went back they are gone again!!! My goodness do something to fix this issue. Rescanned channels it says 42. That's normal but not on the guide again. I'm suck of it. Everyone said get Roku TV ,I did and this is bigger problem than I had with cable. If you offer a product you should provide it and make sure it works. I'm getting another TV wont be Roku will by chrome or apple as add on.
I have all my channels back now also. Apparently, my problem was actually that the cable from the pole to my house was worn and causing "noise" on the line which kept interrupting the signal. Also, FYI, Roku does in fact have an 800 number BUT it is ONLY for newly purchased equipment! No other support is offered. Quite sad.
Like others, the streaming channels disappeared from the Live / Antenna TV portion of my Roku-based TCL TV. All I saw was a list of channel numbers for the off-the-air broadcast channels with no program information. I didn't watch the "live" streaming channels much, but I did want to watch them occasionally. Yesterday I went into the Roku Channel, and looked at the "Live TV" channel list there. That still had all of the channels, with the normal program guide, and my "favorites" still set up.
Just a little while ago I wanted to watch a broadcast channel, so I went into Live / Antenna TV, and the program guide was back. Everything was the way it was before, with the proper channel guide for both Off-The-Air broadcast TV and the "Live" streaming channels.
So if you're seeing the same problem, you might try looking at the live channels from within the Roku Channel app, and see if that returns them to the Live / Antenna TV channel.
I've just suddenly been seeing similar issues, but moreso with the live program guide in the Roku Channel channels! Either it says No Information Available, or on several channels the info is just 100% WRONG!! What it says is playing is NOT what is playing, making a mess even more of a frustrating mess than it already was....