An ad rejection is rarely a mystery. It's almost always one of a handful of predictable problems — and every one of them is catchable before you publish, not after a platform bounces your creative and your launch slips a day.
Here's what actually trips ads up, and how to validate for it up front.
The usual suspects
1. Wrong aspect ratio or dimensions
Each placement wants a specific shape. A 9:16 vertical video that's perfect for TikTok or Reels is wrong for a square feed placement. Platforms either reject the asset or letterbox it into something that performs badly.
Catch it early: validate the asset's dimensions against the target placement's spec before upload — not by eyeballing it in a preview.
2. File size and format limits
Every platform caps file size and restricts formats. Push a video that's too large or in an unsupported codec and the upload fails — sometimes with a cryptic error that doesn't say "file too big."
Catch it early: check file size and format against each platform's published limits as part of your pre-flight, per platform.
3. Copy over the character limit
Headlines, primary text, and CTAs all have limits, and they differ by platform. Copy that fits Meta may be three characters too long for another placement. Some systems silently truncate — which is arguably worse, because your ad ships with a mangled headline.
Catch it early: measure every text field against the destination's real limit and reject overflows instead of trimming them blindly.
4. Ad-policy violations
Restricted claims, prohibited content categories, missing disclaimers — policy rejections are the slowest to resolve because they often involve human review.
Catch it early: run creatives through policy rules before submission so the obvious violations never reach the platform's review queue.
The pattern: validate before you publish
The common thread is that all four are knowable in advance. The platforms publish their requirements; the failures come from not checking against them systematically — especially when you're shipping the same creative to four platforms with four different rule sets.
A good automation layer makes validation the default first step. With Overseer, every creative is checked against each target platform's specs and policy rules before anything is sent:
- Aspect ratios and dimensions
- File sizes and formats
- Text and character limits
- Ad-policy rules
Problems are surfaced and reported up front. Nothing reaches a platform's API until it's known to fit that platform's requirements.
Why this matters at volume
For one ad, manual checking is annoying but survivable. For hundreds of ads a month across TikTok, Meta, Snapchat, and X, manual checking is where rejections — and wasted launch time — come from. Automated, per-platform validation turns "publish and pray" into "publish because it already passed."
Want validation built into your publishing flow instead of bolted on after? That's what Overseer does.