I am using the latest version of PiHole (Pi-hole v5.9 FTL v5.14 Web Interface v5.11), and when I restarted the web server with the command (I did shut down the web server for the weekend)
sudo systemctl start lighttpd
and open the web interface, I am seeing an empty entry in the "Top Blocked Domains" window as depicted with:
Can anybody enlighten me how may I come to such a situation? How can I rectify this?
I did shutdown the web server again, and have restarted it. Still the same above window with an empty line entry. No OS updates have been done over the weekend. I see this kind of behaviour with an empty line the very first time and have not been able to find any other post describing such observation.
I have collected all debug information from PiHole and have uploaded to the tricorder -- respective debug token is available for your convenience.
Do you use any bower plugin ad-blocker? I've seen this before - uBlock origin "hide" one of my top list entries.
Yes, I do have the the "uBlock Origin" ad blocker installed on my web browser, though it says that nothing has been blocked as depicted with:
Today, I do not see any empty lines in the “Top Blocked Domains” window. I will keep this situation under observation.
I think those go together.. only if there is a domain blocked by uBlock you will get an empty line and a message.
I am fairly confident yubiuser's suggestion is correct.
To confirm this, you may run the following command on your Pi-hole machine next time an empty domain reoccurs in the top blocked domain list:
echo ">top-ads(15) >quit" | nc 127.0.0.1 4711
I'd expect that to return a fully populated list of blocked domains, and you should be able to identify the hidden name by its repective count.
And if that's the case, uBlock would be filtering that name from the link in your browser.
Thank you for the pointer, and I will definitely keep this behaviour under observation.
From what I understand the AdminLTE ticket #1549 above, it seems to be that uBlock Origin is indeed an issue with browser-level addon filtering.
I will for sure follow the steps mentioned in case of reoccurrence.
Today, I ran across the same situation as described above that the "Top Block Domains" window shows an empty line next to its counter and the add-on "uBlock Origin" module does not visibly show any blocking activity on the browser bar despite hitting the refresh button on the Edge navigator as depicted with:
Firing the command "echo ">top-ads(10) >quit" | nc 127.0.0.1 4711" on the terminal windows displays the following results:
0 102 keyvalueservice.fe.apple-dns.net
1 20 aad.cs.dds.microsoft.com
2 8 teams.events.data.microsoft.com
3 8 _minecraft._tcp.server.playmonumenta.com
4 8 logs1202.xiti.com
5 8 ww13.smartadserver.com
6 6 apple.com
7 6 sb.scorecardresearch.com
8 5 data.flurry.com
9 4 p37-keyvalueservice.icloud.com
Checking with the "uBlock Origin" logger window, it does indeed show that a domain is being blocked as depicted with:
Anything that can be done here to rectify this misperception ?
Your findings confirm that it is indeed uBlockOrigin that filters ww13.smartadserver.com from Pi-hole's web page in your browser.
You'd have to address this in uBO.
The simplest approach would be to disable uBO for pi.hole.
Alternatively, you may consider to determine the blocklist in uBO that is responible for that filtering and file an issue with its maintainer.
Double-checked the setup and configuration of the uBlock Origin web browser add-on, and have found the solution:
- simply open the uBlock Origin dashboard window,
- under the "Trusted sites" tab, simply add the domain name "pi.hole", and
- click on "Apply changes" as depicted with:
This did indeed solve the problem. Needs to be documented somewhere as a little FAQ item 
Or just click the disable button for pi.hole in uBO's menu (which does the same):
That's what I referred to with: 
