Actually, I meant how long ago was the TVH server installed. There were add-on update failures with CE-installed addons in some of the nightlies. Clearing something out that’s old might be a good idea. Do you have a free SBC or PC you can install the TVHeadend Server on to test it; at least temporarily?
I have nearly the same setup here (HDHR Connect hooked up to TVHeadend, running on CoreELEC on an N2) and it works beautifully. The difference in my case is that TVHeadend is running on a dedicated Odroid C2, instead of on the N2.
Are you running the built-in firewall on CE? If so, try turning that off. Also, are there any IP limitations set for the HDHR on your router?
Another option to test is a direct stream to Kodi. For that, we’d need to create an m3u playlist with a few (3) direct stream links in it.
Create an empty text file named test.m3u. If you go into the web server of the HDHR (http://IP.of.HD.HR/lineup.html), right click on some of the listed channels, copy the URL of 3 of the streams that you know work in the desktop app and paste them into a text document formatted like this:
#EXTINF:1, Test 1
#EXTINF:2, Test 2
#EXTINF:3, Test 3
Save the file, then copy it over to Playlists folder in the Userdata SMB share. Try opening the streams by going into Kodi’s video playlists. By all means this should work, but then I can’t test it at the moment to guarantee it (it works fine in VLC however). If the streams don’t work, it might be that something on your network is blocking things to the N2.
That M3U file can then be added as an IPTV network to your TVHeadend server. If it works there, it makes me think there’s something weird going on with the HDHR driver in TVH.