VAST Error 604: No supported Companion resource found

The player could not find a Companion resource with a supported type. In operations, this usually shows up when the companion package does not include a resource type the environment can render.

This is the kind of issue that is easiest to solve when the investigation starts from the right evidence path. VAST Inspector is usually the fastest first step because it confirms whether the response, wrapper chain, or media selection behaves the way the player expects.

This is a resource-compatibility problem rather than a missing-asset problem, so the focus should be on what formats are actually available.

The most common causes are unsupported companion resource formats, missing fallback options, and creative packaging aimed at a different environment. Teams often treat the visible error as the root problem, but in practice the real issue may sit earlier in the wrapper path, in the creative package, or in the environment assumptions around the request.

That is why it helps to compare a failing request against a known-good example. Once you know whether the difference is structural, timing-related, or environment-specific, escalation becomes much faster and cleaner.

VAST Inspector should be the first stop for this class of issue. From there, move into VAST Error Code Explainer to narrow the failure further.

A useful investigation should end with concrete evidence: the failing tag or asset, the exact point where the player behavior diverged, and the partner or configuration change most likely responsible. That turns a generic player code into an actionable support ticket or launch fix.

Inspect the companion resource types returned and compare them with the placement's real rendering capabilities before approving the creative package.