Randomly losing connectivity to my HA instance via duckdns (log of SERVERFAIL errors)

Hi, all. I have an issue, where I randomly cannot connect to my instance, using duckdns. When at home I can always connect using local IP address, but while using dns name, it randomly cannot connect, giving me error

Unable to connect to Home Assisntant 
Settings-Refresh external url-Wait

IF i check HA DNS logs I see that there are lot of SERVERFAIL errors
Could someone please explain what those mean and how to fix them.

[INFO] 127.0.0.1:44634 - 56093 "A IN www.duckdns.org. udp 44 true 2048" SERVFAIL qr,rd,ra 33 0.015144s
[INFO] 172.30.33.3:55389 - 56093 "A IN www.duckdns.org. udp 33 false 512" SERVFAIL qr,rd,ra 33 0.023188588s
[INFO] 172.30.33.3:48147 - 56093 "A IN www.duckdns.org. udp 33 false 512" SERVFAIL qr,aa,rd,ra 33 0.000193646s
[INFO] 172.30.33.3:33844 - 56093 "A IN www.duckdns.org. udp 33 false 512" SERVFAIL qr,aa,rd,ra 33 0.000187072s
[INFO] 172.30.33.3:36171 - 56093 "A IN www.duckdns.org. udp 33 false 512" SERVFAIL qr,aa,rd,ra 33 0.000184313s
[INFO] 172.30.33.3:41387 - 56093 "A IN www.duckdns.org. udp 33 false 512" SERVFAIL qr,aa,rd,ra 33 0.000253182s
[INFO] 172.30.33.3:34767 - 56093 "A IN www.duckdns.org. udp 33 false 512" SERVFAIL qr,aa,rd,ra 33 0.000220608s
[INFO] 172.30.33.3:42549 - 56093 "A IN www.duckdns.org. udp 33 false 512" SERVFAIL qr,aa,rd,ra 33 0.000377385s
[INFO] 172.30.33.3:45732 - 56093 "A IN www.duckdns.org. udp 33 false 512" SERVFAIL qr,aa,rd,ra 33 0.000221645s
[INFO] 172.30.33.3:46265 - 56093 "A IN www.duckdns.org. udp 33 false 512" SERVFAIL qr,aa,rd,ra 33 0.00032007s
[INFO] 172.30.33.3:49932 - 56093 "A IN www.duckdns.org. udp 33 false 512" SERVFAIL qr,aa,rd,ra 33 0.000253386s

I have tried changing HA dns to 1.1.1.1 or 8.8.8.8 or setting my ISP DNS addresses. Nothing seems to help. The issue some times is rare, sometimes it is really difficult to connect to my instance.

Board:RP4
IP settings: static
Connectivity: Wired

Also I have this configuration, but it says invalid local network URL

for me i have lots of warning in the DuckDns logs :

[19:13:34] WARNING: 
[19:18:39] WARNING: 
[19:23:44] WARNING: 

and google assistant dont work anymore…

seems there is a problem with DuckDNS servers…not the first an not the last time for sure…just wait tomorow to see…

There are fews Warnings in DuckDns, but not many. Maybe it would be good thing to migrate to cloudflare…

i have couple of month ago…but its worth than DuckDNS because FreeNom doesnt work anymore, i mean for free, so you have to buy a domain name.

The config is really much complicated than DuckDNS too…

How are you providing HTTPS access? Are you using a LetsEncrypt certificate directly on HA, or using nginx, or… ?

Using letsencrypt certificate, via duckdns addon.

That’s what I figured.

From your questions, it appears you lack foundational knowledge of certificates and dns. Duckdns is likely working just fine as intended - I’ve literally never once had an issue with mine.

Either your network is miaconfigured, or your HA instance is, or possibly both.

However, this much is for sure - once you configure HA with a certificate, it will no longer respond to http requests, and will only respond to https. This fact is the source of your configuration warning about your internal url.