On Wed, 10 Jan 2018, ghanashyam satpathy via curl-users wrote:

> Following are the library version I am using.
>
> libcurl - 7.50.3
> openssl - 1.1.0 b
> McAfee WebGateway 7.7.2.6.0
>
> Very much reproducible using Fiddler as a proxy that requires
> authentication(basic), just supply invalid credential to libcurl. The
> curl_easy_perform() will return CURLE_RECV_ERROR (56)

So since we're on the curl-users list:

Can you show us the full verbose output curl and your proxy says and returns
when you use the wrong credentials?

  "curl -v -x http://name --proxy-user foo:bar --proxy-ntlm http://example.com"

replace 'name' with the host name or IP address if your actual proxy.

-- 
  / daniel.haxx.se
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