VAST Error 600: General CompanionAds error
The companion ad (the banner shown next to the video) failed for an unclassified reason — catch-all for companion problems.
Companions are display units rendered outside the player — beside it, below it, in a designated page slot — synchronized with the video ad. Error 600 is the general failure bucket when a companion can't be shown and no specific 601–604 applies.
Companion failures usually trace to the page/app integration (the slot) rather than the creative: the video plays fine, the companion has nowhere to go.
Why error 600 happens
No companion slot wired up
The page or app never registered a companion zone with the player SDK, so there's nowhere to render.
Slot/creative wiring errors
The integration passes wrong slot IDs or renders companions into removed DOM elements.
How to fix VAST error 600
- 1
Verify the companion zone registration
Confirm the page defines companion slots with the player SDK and that their IDs match what the integration expects.
- 2
Check the specific codes
601 (size), 602 (required), 603 (fetch), 604 (type) each name a concrete cause when reported.
Seeing error 600 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 600 — frequently asked questions
Does a failed companion block the video ad?+
Only if the companion is declared required (see 602). Otherwise the video plays and the companion failure is reported separately.