VAST error codes / Ad type and trafficking
VAST error 206: Ad break shortened, ad not served
Short answer: The break was cut short, so the ad never got a slot to play in. Introduced in VAST 4.1.
What your player reported
206· Ad Break shortened. Ad was 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 player or SSAI layer reduced the length of the ad break after the ad was already selected. The ad was dropped rather than truncated, so this is a scheduling outcome, not a defect in the tag.
Common causes
- A live break ended earlier than the scheduled duration
- SSAI filled the break with earlier ads and ran out of room
- Total duration of selected ads exceeded the break, and this one was trimmed
- `<Ad sequence>` placed the ad late in a pod that got cut
How to fix it
Usually nothing in the XML needs changing. Confirm the creative duration matches what the break was sold at, and check pod ordering if a specific ad keeps losing its slot. Validate durations so a mismatch is not what makes the break overrun.
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-linear-duration: <Linear> must contain <Duration>
- VAST-2.0-ad-sequence: Mixed use of sequence attribute across <Ad> elements in a pod
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.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.