I\'m installing Crashlytics for my iOS app. I downloaded it via their site link, and went through all the steps for integrating the frameworks, adding the run script, etc. <
TL;DR
Tap your scheme -> edit scheme -> set build configuration to "Release"
Explanation:
The most voted answer sounds about right, but there are situations where you just don't need crashlytics in debug builds (who wants crashes sent when you just develop and experiment with your code?). In this case you should disable crashlytics by checking debug compilation flags (out of scope of this answer) and for the first time during installation build app for release to let crashlytics know that you built app.