First of all - very very sorry about the crashes!
Here are two quick fixes you should try to see if it works:
1. Force quit the app (e.g. on iPhones that means double clicking the Home-button, and swiping up on the app to close it. Then open again)
2. Delete the app and download it again from the App Store / Play Store. Your profile and posts are safe, and this shouldn't take more than a few minutes.
If the problem persists, please reach out to us at firstname.lastname@example.org!