Curl -6 aka IPV6 not resolving host using HA Terminal?

I run HA out of VirtualBox so this issue might have more to do with virtual machine networking (not my skillset!) than Home Assistant, but with regards to the following command…

curl -6 'http://umbrel.local:8332/' -u 'umbrel:PASSWORD' -d '{"jsonrpc":"1.0","id":"homeassistant","method":"getblockcount","params":[]}' -v

On my desktop Terminal I am given the correct JSON response. Unfortunately HA Terminal spits out the following error…

* Could not resolve host: umbrel.local
* Closing connection
curl: (6) Could not resolve host: umbrel.local

Any thoughts?

If I use -4 / IPV4 then I am able to connect to the server (both on desktop and HA Terminals) however no JSON response is given in either instance. Thanks.

Does anyone know if my issue is related to this?