Hi Jan Niklas,
don’t know how to set the cacerts_path, but you could place your corporate certs in the castore that is used by the tailwind installer (and the following esbuild installer as well). Just paste the certificates to the end of deps\castore\priv\cacerts.pem. Make sure to delete the folder _build\dev\lib\castore before running mix phx.server again.
To get the corporate cacert you could try to export it with the edge browser when you open a corporate page or the proxy’s login page an click through the options an icons in front of the address bar: lock → lock → certificate icon next to the x icon → details → select uppermost cert → export.
I hope it works for you.
Cheers, Marco
