card not found under VPN (Tailscale)

[DrConradInTheHouse]

I have this simple card, in HA running as a docker container, that works perfectly on WiFi. However when I'm away from home and then on tailscale VPN the card cannot be found.
I thought this might be the VPN but there are no issues or logs that indicate a error.
All other cards and custom cards work fine. All other HA functions are perfect.
I installed this card from HACS.
Could it be that this card is using a resource that isn't visible inside a VPN for some reason...as I say all other HACS custom cards are fine so I'm using inverse logic to remove HA, HACS, WIFI, VPN, as the root cause, which only leaves this card / setup
?

[DrConradInTheHouse]

FIXED

Issue was the mobile phone settings was using a custom DNS that was not resolvable. I could have added a route to Tailscale but just chose to remove the custom DNS

I haven't looked at the source code for your card yet but why does the card need to resolve some host name once installed... No the cars I'm about 40 custom ones requires this. It's a slight concern at the moment hopefully you can attend to the issue and explain.