When you click on a promotion you get "promotion is no longer available"

This happens when too many other users clicked before you on adverts and the quota of an advertiser has been exhausted.

If you have not reloaded your Account Overview for a long time, then it is highly probable that old promotions are on your page.
The best solution is to click on "Reload" before clicking an action. Then this message should appear only seldom.

The promotion is still available when the page loads.

If you click, the budget of the provider has already been consumed.
This means enough other users have clicked during your viewing time.

The budget can be configured by all advertisers.