Hello zelstark,
It sounds like GarageBand isn't working as expected on your iPhone. In this case, we'd use the following steps to troubleshoot the issue: If an app on your iPhone or iPad stops responding, closes unexpectedly, or won’t open - Apple Support
If an app on your iPhone or iPad stops responding, closes unexpectedly, or won’t open
If an app on your iPhone or iPad doesn't work as expected, try this.
1. Close and reopen the app
Force the app to close. Then open the app to see if it works as expected.
2. Restart your device
Restart your iPhone or restart your iPad. Then open the app to see if it works as expected.
3. Check for updates
To see if updates are available for the app, open the App Store, tap your profile icon, then scroll down to see if updates are available. If updates aren't available for the app, update the software on your iPhone or iPad.
4. Delete the app, then redownload it
Delete the app. When you do this, you might lose data that was stored in the app. Then redownload the app. Then check to see if the problem with the app is fixed.
Get more help
* If the App Store itself is not responding, contact Apple Support for your iPhone or for your iPad.
* If you found the app on the App Store, contact the app developer. If the app is made by Apple or came with your iPhone or iPad, contact Apple Support for your iPhone or for your iPad.
* If you bought the app recently and you no longer want it, you can also request a refund.
These steps include updating and reinstalling the app. Which should solve this issue. If not, please reply back to let us know if you're able to restart the Mac to solve this?
Hoping to hear how it goes.
Take care.
