API error type

Proxy validation failed

HTTP 422 https://errors.driftstack.dev/proxy-validation-failed

What it means

The proxy attached to this launch failed a LIVE pre-launch connectivity test — the server connected THROUGH your proxy and ran a real egress round-trip, which did not succeed. The launch was blocked before any session or worker started. The body carries a reason: unreachable (host/port wrong or offline), auth_failed (bad credentials), timeout (proxy too slow), or egress_blocked (proxy connects but its upstream can’t reach the internet).

How to fix it

Fix the proxy per the reason — verify host/port and that it is online, re-enter credentials, or check the proxy’s own upstream egress — then launch again.

Where it appears

In the type field of the RFC 9457 application/problem+json error body, alongside title, status, detail, and an instance correlation id.