GL-MT3000 Tailscale custom exit node

I am running into an issue trying to use Tailscale custom exit node feature on my GL-MT3000. I have two MT3000 units. Unit A is set up as a Tailscale exit node at Location A, and Unit B is a traveling router set up as Tailscale connected to the custom exit node (Unit A).

I have used the Unit A as a Tailscale exit node with other devices (phone, PC) extensively without issue. However, I cannot get Unit B to work when connected to Unit A as the custom exit node. Whenever I apply the custom exit node, the Internet stops working for all devices connected to Unit B. From my initial observation, it may be a DNS issue, because I can ping all IP addresses after connecting to custom exit node but cannot resolve hostnames. However, I am not sure what the exact issues are or how to troubleshoot why hostnames are not resolving correctly.

Any advise on how to troubleshoot this?

It looks like the DNS issue of the Unit B I think so.

  1. You can try to set the customize DNS Server(like 8.8.8.8/1.1.1.1) on Unit B GL GUI > NETWORK > DNS.

  2. You can try to unbind the Tailscale on the Unit B (including in GL GUI > Application > Tailscale and the Tailscale official dashboard), and reset the Unit B, and re-bind/re-configure it again.