I've been having an issue with Tailscale on Android since setting up Tailscale on my network. The client will connect no problem, and it will accept my override DNS setting pointing to my Pi-hole. It will resolve domains via the Pi-Hole, which I can confirm by navigating to custom dnsmasq entries served by the Pi-Hole.

After some period of time -- generally a couple hours or so -- the Tailscale Android app will show a red exclamation point next to the "Connected" status message. Tapping on it to view the health warnings reveals the following:

"DNS Unavailable Tailscale can't reach the configured DNS servers. Internet connectivity may be affected."

Usually when this message first appears, I actually do still have access to my DNS server. I can ping the host and I can still resolve custom dnsmasq entries. Eventually, however, I will lose connection entirely and will not be able to resolve any DNS until I toggle the Tailscale connection. (Perhaps this is something to do with DNS TTL?)

I've tried Googling around and have seen suggestions to disable MagicDNS, which did not resolve the issue. Other clients (desktop in both Linux and Windows) appear to be unaffected.

Any help would be very much appreciated. :)