Hopefully this is the correct channel for such a question and my quest for further knowledge.

I've currently built a significant platform which allows clients to communicate with our API, which in turns allows "items" to be pushed to a print queue.

Most third party developers and app users have no problem consuming the API, and I only assume this is because they authenticate over basic auth outside a proxy environment.

We have one client, that appears to be locked behind a proxy of sorts, which prevents the consumption of a particular endpoint. I'm regrettably faced with the 407 - Proxy Authentication Required.

I'm very keen to understand is this something the end user (client) should resolve by adjusting proxy security settings (if needed) or a developer problem?

I'm also keen to understand what is actually happening? End user behind proxy calls the API, to try and authenticate via basic auth, and then tries to authenticate via proxy-authenticate?

Ideally not looking for a fix but more knowledge on what is happening, so I can fix myself.

  • When you say client, you mean customer or http client (app)?
    – Laiv
    Feb 7, 2018 at 19:24
  • @Laiv Yes, Customer, my apologize. I guess it can be interpreted in a different context. Feb 7, 2018 at 19:51
  • Are you sure that is your proxy the one returning the 407? If yes. Can you track the http headers sent by the customer's http clients? Maybe their network configuration (topology) is messing with the HTTP headers. I have seen similar problems with websockets or clients getting access to internet via Vpn and/or Proxies
    – Laiv
    Feb 7, 2018 at 19:57

1 Answer 1


Your consumer is probably accessing your API from behind a proxy. Do it's completely his/her responsibility to handle this.

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