yarn - info There appears to be trouble with your network connection. Retrying...

Solution 1.

yarn install --network-timeout 1000000

Solution 2.

yarn config delete https-proxy
yarn config delete proxy

Debug

yarn install --verbose

My issue was that i forget to add the license key in .yarnrc.yml for Font Awesome Pro.

npmScopes:
  fortawesome:
    npmAlwaysAuth: true
    npmRegistryServer: "https://npm.fontawesome.com/"
    npmAuthToken: "your-token-here"