VAST Error 602: Required companion could not be displayed

One or more required companion creatives could not be displayed. In operations, this usually shows up when the environment required a companion that was unavailable or unusable.

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 can block revenue even when the main linear ad is otherwise healthy because the campaign rules depend on the companion requirement.

The most common causes are required companions missing or unusable, layout constraints preventing display, and trafficking assumptions that did not match the page or app surface. 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.

Confirm whether companions are required for the campaign, then verify the returned companion assets and the available display surfaces together.