VAST Error 604: Companion resource type not supported
None of the companion's resource types (static, iframe, HTML) can be rendered by this integration.
Same as 503 but for companions: the integration renders (say) static images only, and the tag offers only an HTML companion. No renderable variant, error 604.
Why error 604 happens
HTML-only companion on a static-only integration
Many app SDK companion zones accept images only; rich HTML variants have no fallback.
Unsupported image format
Modern formats on old integrations get rejected at the type check.
How to fix VAST error 604
- 1
Always include a static PNG/JPEG variant
Guarantees a renderable option on every integration type.
- 2
Check the integration's supported resource types
Match trafficked variants to what the placement documents.
Seeing error 604 on a live tag?
Paste the tag URL or XML — the validator resolves the full wrapper chain, validates the schema, downloads every media file, and shows exactly which stage fails.
Validate your VAST tagVAST error 604 — frequently asked questions
Should companions be HTML or images?+
Ship both. HTML where supported gives interactivity; the static variant is the compatibility floor that prevents 604s.