VAST error codes / Wrapper errors
VAST error 300: General wrapper error
Short answer: Something failed while resolving the wrapper chain.
Inspect the wrapper chain first
VAST error 300 is a wrapper-chain failure. Inspect each hop, then test the resolved tag.
What your player reported
300· General Wrapper error.
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
A catch-all for wrapper resolution problems that are not a timeout (301) or depth limit (302).
Common causes
- Malformed wrapper that resolves to nothing usable
- A hop that returns an error document instead of VAST
How to fix it
Walk the chain hop by hop in the inspector. 301 and 303 are the specific cases you usually land on.
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-2.0-wrapper-vastadtaguri: <Wrapper> must contain <VASTAdTagURI>
- VAST-2.0-wrapper-impression: <Wrapper> must contain at least one <Impression>
Related error codes
- VAST error 301: Wrapper timeout / URI unreachable
- VAST error 302: Wrapper limit reached
- VAST error 303: No ads after wrappers
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