VAST error codes / Linear and media errors
VAST error 411: Mezzanine failed spec
Short answer: A mezzanine was provided but did not meet required specs. Introduced in VAST 4.1.
Debug this tag now
If you only have a live URL, test it first. If the failure is in the wrapper chain, inspect each hop. Validate resolved XML when you already have the response.
What your player reported
411· Mezzanine was provided as required, but file did not meet required specification. Ad not served.
Wording from the IAB VAST 4.3 specification error table. Players may shorten or reformat it, but the code is the same.
What it means
The `<Mezzanine>` was present but its format, dimensions, or delivery did not satisfy the platform requirements, so the ad was not served.
Common causes
- Mezzanine resolution, codec, or bitrate outside spec
- Wrong `delivery` or `type` on `<Mezzanine>`
- Missing required width/height
How to fix it
Match the mezzanine to the platform's exact spec. vastlint checks mezzanine type, delivery, and dimensions.
VAST error codes are runtime buckets emitted by the player. They tell you where the failure happened, not which line of XML caused it. Paste the raw tag into the validator to map this code onto the exact element and rule.
Related vastlint rules
- VAST-4.1-mezzanine-type: <Mezzanine> missing required type attribute
- VAST-4.1-mezzanine-delivery: <Mezzanine> missing required delivery attribute
- VAST-4.1-mezzanine-width: <Mezzanine> missing required width attribute
- VAST-4.1-mezzanine-height: <Mezzanine> missing required height attribute
Related error codes
Debug this tag now
Validate the XML, follow the wrapper chain, or check it in CI before launch:
# CLI: exits non-zero on errors, ideal for pipelines
vastlint check creative.xml