@Joesmith say are you using iOS version 10? If so here some information that might help.
MariamFitbit Premium User MariamFitbit
Moderator
Aug 22
Please make sure you do have the latest version downloaded, cause it definitely works better than the previous version and it's not supposed to be crashing. Do the following to see what version of the Fitbit app is installed on your device:
Tap the Account tab.
Tap Help. You'll see the app version at the top of the screen. Unlike the image the image below, you app should say 568 which is the latest version.
User-added image
To update the Fitbit app to a newer version:
On your iOS device, tap App Store.
Tap the Updates tab.
If a Fitbit update is available, you'll see Fitbit in the list of pending updates.
Tap Update.
Hope this helps. Keep me posted! Cat Very Happy