Weight & build
Creative does not match declared size
What Google's rule says
Google's stated rule is that the creative's dimensions do not match the ad slot size returned by the ad server. Note which two things are being compared: the rendered creative against the slot the ad server filled, not against the size the creative was uploaded as.
What actually causes it
- A creative uploaded against the wrong size in the ad server.
- An HTML5 bundle whose stage size differs from the size it was trafficked as.
- A responsive or fluid build that resolves to something other than its declared dimensions.
- A tag reused from another placement of a similar but not identical size.
How to fix it
Compare the rendered dimensions against the size the ad server returned for the slot, not against the placement you meant to book. Those are different numbers whenever the request carried more than one eligible size.
The part that is not obvious
The comparison is against the slot size the ad server returned, which is not the same thing as the size on the insertion order. A multi-size request can legitimately be filled at any of its eligible sizes, so a creative that is correct for the placement can still be wrong for the slot it landed in. That makes this reason a trafficking mismatch far more often than an artwork mistake — the file is the size someone intended, just not the size the auction asked for.
Related reasons
Reason name verified against Troubleshoot creatives rejected by Display & Video 360 or Google Ad Manager on 30 July 2026. The causes and fix above are practitioner guidance, not Google policy text.