Here is the instructions to do tracking settings when creating campaigns for TrueView (Android/iOS).
You are supposed to complete the conversion tracking settings.
Check here for the instructions if you have not finished the conversion tracking settings.
1. Select "+CAMPAIGN" > "Video".
2. Select "Mobile app installs" in "Type" section and search/select the desired app in "Your mobile app" section.
3. The following page appears after "Create campaign" and "Create an ad group and ad" are completed. The conversion tracking will be linked.
The settings are completed.
Check here if you have not finished the postback settings.