I regularly have a prblem with deb.devuan.org.
The trouble is that I connect to wifi using connman, and it caches
the IP numbers for domain names. It also rewrites the /etc/resolv.conf
file so it gets all domain-name looup requests.
One time years ago the round-robin in deb.devuan.org gave me
a dud server, and connman cached it.
Every time since, I always connects me to that same IP number,
which still does not work.

To reach deb.devuan.org I overwrite the /etc/resolv.conf
*after* connecting to wifi. I set it to look at some well-known public
DNS resolver, such as 1.1.1.1.
That bypasses the corrupted cache, and acessing deb.devuan.org
works properly.

I have found no method in connman to clear its private DNS cache.
If anyone knows of one, I would love to know it.

-- hendrik