Proxy Digest Authentication in Requests
Distinguish Requests destination Digest authentication from proxy Digest and its HTTPS tunnelling requirements.
Requests' HTTPDigestAuth handles destination authentication. A proxy instead issues status 407 with Proxy-Authenticate and needs its own authentication handling.
requests-toolbelt supplies HTTPProxyDigestAuth to process proxy challenges and prepare proxy authorization. Check compatibility with the exact Requests and transport versions in use.
HTTPS CONNECT needs separate support
A proxy can challenge while establishing the CONNECT tunnel, before an ordinary destination response reaches response hooks. Handling a visible 407 therefore does not establish support for every CONNECT authentication path.
For HTTPS targets, use a client or maintained integration that explicitly supports the required proxy authentication at tunnel setup. Monkey patches tied to old Requests or urllib3 internals need a maintained compatibility statement before reuse.
Record proxy and destination authentication requirements in separate fields, including the stage that failed. This shows which challenge was handled and which still needs support.