2019.12.27.0617 Channels DVR not seeing my HDHomeRun tuners only TVE ... The Clients see the tuners fine all on the same switch. Says I have to add them by IP. My other instance of DVR Version 2019.12.18.2234 sees all the tuners fine same switch,
My Tuners ...
I checked the logs nothing there the scan just will not pickup the tuners.
You will need to input the IP addresses by adding source and select HD Homerun Device.
You can't run two instances of Channels DVR at the same time my understanding.
Why should I have to all other devices on the same switch find the tuners including my 2nd Channels DVR. I have been running 2 instances of DVR since the start I simply turned of bonjour and outside access on my 2nd DVR.
2019/12/27 07:54:43 [SYS] Starting Channels DVR v2019.12.27.0617 (linux-x86_64 pid:30745) in /volume1/@appstore/ChannelsDVR/channels-dvr/data
2019/12/27 07:54:44 [HDR] Found 0 devices
2019/12/27 07:54:46 [SYS] Started HTTP Server
2019/12/27 07:54:47 [DVR] Recording engine started in /volume1/ChannelsDVR
2019/12/27 07:54:47 [SYS] Bonjour service running for dvr-edsynology.local. [192.168.1.221 192.168.1.223]
2019/12/27 07:54:47 [NAT] Successfully mapped port 8089 using natpmp
2019/12/27 07:54:47 [DVR] Waiting 4m42.91737639s until next job 1577462370-395 The Librarians
2019/12/27 07:54:49 [SYS] Created database snapshot: backup-20191227.075448
2019/12/27 07:54:49 [SYS] Removing old backup backup-20191216.121512
If you switch back to an older known working version of the DVR server does it work?
(To revert back to an older version, simply change the latest symlink in your install. For your situation, something like:
$ cd /volume1/@appstore/ChannelsDVR/channels-dvr
# ln -sf 2019.12.24.0809 latest
Or, if you prefer the one-liner: cd /volume1/@appstore/ChannelsDVR/channels-dvr; sudo ln -sf 2019.12.24.0809 latest.)
Thanks I am at the moment reinstalling to see if something got corrupted.
I restored it to my 2nd DVR all and guide data etc... works fine so that leads me to think my router or something is blocking my Synology going to reboot my network.
Feel like I am talking to myself 
Well, sometimes documenting your steps for yourself helps you see a thread that was difficult to find before. Hopefully it works out for you.
I gave up could not get it to scan the tuners no matter what I tried. the HDHomeRun DVR on the same synology had no problem scanning the tuners ... I resorted to adding each tuner individually.
Channels DVR really gives no debugging other than 0 tuners found. which I already knew
Maybe update HDHR firmware?
This just happened overnight could not detect my tuners ... I keep all my systems up to date. I run Plex , HdHomeRun dvr and a windows VM and the only thing that did not find the tuners was Channels DVR.
Sounds like a network issue where the HDHR discovery UDP packets are not making it to the dvr. Could be a firewall or something else.
If you add tuner by IP manually it will use TCP and should work more reliably