If your In-App campaign was working properly while testing but after campaign creation, it is showing zero impressions on the dashboard, it could be due to one of the following reasons:

• None of the customers will be fulfilling your segmentation/targeting criteria
• Users whom you have targeted, might not have opened the app. In-app campaigns are shown only when user opens the app after you create the campaign.
• Time difference between campaign creation and expiry time is too less and none of the users would have opened your app during that interval
• If you are targeting an In-app campaign to be shown on a particular screen, make sure that you have selected the right screen name. 
• InApp module is not integrated. Please go through the link to integrate in-app SDK -  developer guide

• showInApp() not called on the screen on which the campaign needs to be shown. 

• There are multiple campaigns created with the same trigger and segment filters but the priorities are different, so the campaign with the higher priority would be delivered to the user.

• The campaign might not show up because of the global delay condition. 

• In case of a similar priority, campaigns with the latest updated timestamp would be delivered first to the user.