VAST error codes / NonLinear and companion
VAST error 501: NonLinear dimensions do not fit
Short answer: The overlay is too large for the display area.
What it means
The non-linear creative's dimensions do not align with the available overlay area.
Common causes
- Overlay larger than the slot
- Missing or wrong width/height on `<NonLinear>`
How to fix it
Set `<NonLinear>` width and height to fit the slot.
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-nonlinear-dimensions: <NonLinear> missing required width or height attributes
Related error codes
- VAST error 500: General NonLinearAds error
- VAST error 502: Cannot fetch NonLinear resource
- VAST error 503: No supported NonLinear resource
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.xmlUse the right tool for this failure
If you already have the resolved XML, run a pure spec check. If you only have a live tag URL, test that endpoint first. If the failure happens in the wrapper chain, inspect each hop.