VAST Error 410: Verification unit not executed
A measurement/verification script attached to the ad (via AdVerifications) failed to run — the ad may have played unmeasured.
VAST 4.1 formalized verification vendors (OMID scripts) in <AdVerifications>. Error 410 means a declared verification resource didn't execute — blocked, failed to load, or unsupported by the player.
The ad itself often plays fine; what's lost is the measurement. For buyers who require verified impressions, that can matter as much as playback.
Why error 410 happens
Player lacks OMID support
Verification scripts need an OM SDK integration in the player. Without it, every declared verification fails.
Verification script fails to load
The vendor's CDN is slow or blocked (frequently by privacy tooling), so the resource never initializes.
Too many vendors attached
Multiple verification scripts multiply load time and failure probability; the slowest one fails first.
How to fix VAST error 410
- 1
Verify OM SDK presence on the inventory
Confirm the placements run an OMID-capable player version; verification simply can't execute otherwise.
- 2
Check the verification resource loads
Fetch the JavaScriptResource URL from the tag directly and confirm it's reachable and fast.
- 3
Trim redundant vendors
Each extra verification vendor adds failure surface. Keep the ones the buy actually requires.
Seeing error 410 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 410 — frequently asked questions
Does a 410 invalidate the impression?+
The impression usually still counts, but it may be unmeasured or flagged by the buyer's verification vendor. High 410 rates on a deal can trigger billing disputes even when playback was perfect.