Why my LinkedIn job ad campaign completely flatlined (0% conversion)

I wanted to share a quick acquisition failure I just went through, as it might save someone here a few thousand dollars and a couple of wasted weeks.

I recently launched a white-label niche job board platform built around organic search and SEO-first growth.

My first attempt at finding early adopters was LinkedIn Job Ads. I targeted titles like:
• Owner
• Small Business Owner
• Talent Acquisition Specialist
Result:
124 views.
0 applicants.
Complete flatline.

In hindsight, the audience overlap was basically zero.

I was advertising through a channel designed for people looking for employment, while the actual users for something like this are more likely to be operators already building niche sites, side projects, or SEO-driven assets.
The mistake seems obvious now, but at the time, it felt logical enough to spend money testing.

So instead of continuing with paid ads, I’m trying a much smaller and more direct approach.

My target was a handful of early adopters to launch niche job boards on their own domains/brands. I’m waiving all platform fees for the first 6 months to build a solid user base before the full launch. The operators keep the employers' revenue. My team handles the platform side.

Initially, LinkedIn seemed a good option but obviously not! Lesson learned.

Mostly posting this because I’m curious whether anyone else here has had a channel mismatch that only became obvious after spending the money.

What acquisition channels actually worked for your early B2B launch?