CB

Guzzle isn't able to connect through the proxy when making requests resulting in them failing. This needs to be set per-client so is an implementation problem as all Guzzle usages would need to be updated, which if we're to do that we might as well move to Symfony HTTP Client instead (planned for CB 3.x). Needs further review as only way to globally do this is middleware, which again requires changes to every Guzzle call.

https://docs.guzzlephp.org/en/stable/handlers-and-middleware.html?highlight=default#middleware

https://www.joomlapolis.com/forum/153-professional-member-support/243757-internet-access-what-to-whitelist#329695