Content.ad is a CPC (cost-per-click) platform.
Advertisers are not guaranteed that they will receive clicks as it is dependent on the CPC bid price, the click-through rate of the advertiser's campaign, and competition from other advertisers in the system.
For example, if you're bidding $0.08 on a weight loss ad and there are other advertisers bidding $0.10 on their weight loss ads, then the $0.10 campaigns will serve before the $0.08 campaign.
If you aren't getting traffic to your ads, one possible explanation is that your bids are too low. Reach out to an Account Manager if you need help setting your bids.