There is a number of reasons why a campaign is not getting traffic, or why a campaign that used to get traffic suddenly gets none.
Check your account balance.
Campaigns are stopped if there is insufficient funds on the balance.
Check your campaign status and budget settings.
When your campaign daily budget is reached, your ad will no longer run for that day and will run the next day until you pause the ad or the total campaign limit is reached. When your campaign total budget is reached, your ad will stop delivering unless you increase the limit and restart the campaign.
Check the campaign settings.
Use our Traffic Estimator to see how many estimated impressions is available according your campaign’s bid and targeting settings.
Campaigns targeting high quality countries and popular ad placements (zones) must have very competitive bids to be able to receive traffic, and the prices change frequently as we operate in real time.
Please refer to our documentation for more details about campaign settings.