Why is my ad active but not spending?

Where a platform publishes an audience floor, the usual cause is that the audience fell below it once split across test cells — the floor applies per cell. Where no floor is published, delivery is governed by the auction, and the common causes are an unfinished learning phase, a special ad category restricting targeting, or a bid below the auction floor.

What is the minimum audience size for LinkedIn ads?

LinkedIn requires 300 members, applied per cell. A two-cell test therefore needs at least 600 in total. It is the only platform of the eight we track that publishes such a number.

How to fix an ad that is not delivering

A campaign that spends nothing usually isn't broken. But "your audience is too small" is the first thing anyone is told, and on seven of the eight platforms we track there is no published number behind that advice.

Who actually publishes a floor

Platform	Minimum audience	Spec verified
Meta (Facebook and Instagram)	not published	not verified
LinkedIn	300	2026-08-10
TikTok	not published	2026-08-10
Google Ads	not published	not verified
YouTube	not published	2026-08-10
Pinterest	not published	2026-08-10
X	not published	2026-08-10
Reddit	not published	not verified

Read from the same platform data our app checks against at runtime. 1 of 8 platforms publish a minimum audience size. Where this says "not published", it means we looked and the platform doesn't state one — not that the number is zero, and not that we failed to find it.

The arithmetic that catches people

Where a floor does exist it applies per cell, not per campaign, and that is the trap. A 500-person LinkedIn audience clears the 300 floor comfortably. Split it into two test cells and each holds 250. Both are under. The campaign's live, the status says Active, and neither cell delivers.

So the number to check is floor × cells.

When no floor is published

On the other seven, delivery is governed by the auction rather than by a stated threshold, and a stalled campaign is more likely to be one of these:

The learning phase never exits. Under roughly 50 optimisation events a week per ad set, most platforms keep the ad set in learning, where delivery is conservative and the reported cost per result is noisy rather than informative. Editing the ad set restarts it.
A special ad category is set. Housing, employment and credit campaigns lose most targeting options by design. The campaign runs; the audience is not the one you selected.
The bid is below the auction floor. Nothing errors. The ad just never wins an impression.

What we could not check for you

Whether your specific audience clears anything. No tool outside your ads manager can see your forecast panel, and any tool that claims otherwise is guessing. Read the number there before launching.