It may also be because the Campaign is not filling out advertisements, and you have not added devices as test devices to make advertisements fill up.
This is easy to overlook, because at first the advertisement can be filled - only during testing will they simply cease mysteriously.
Chartboost has a parameter:
Edit the campaign you use for testing
- In the "Campaign Logic" section, click the "Show Test Devices" button.
- Click Add Test Device to add each device.
- Turn on each device and save the campaign.
(Remember to tag them when you live), as I assume that means that these devices continue to see ads, but you probably want to see how the application really works)
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