Flutter iOS App crashing in Testflight but it is working in debug mode

When we tried background audio in debugging mode everything was working fine. We need this package to work the alarm in background mode i.e., when the app is idle in IOS. This functionality is required in our application to play an alarm when we receive a signal from server even though the app is idle, we need to hear the sound as alarm. It worked when we connect it in debugging mode and we have proceed to TestFlight update but app from the TestFlight crashed when the screen is off may be in the background mode.The issue occurs particularly in iOS

To Reproduce

Steps to reproduce the behavior:

1.Added alarm library in our flutter project

2.Coded like play alarm when we receive a signal from server

3.Enabled background fetch and audio airplay or picture in picture in capability.

4.Tested in debugging mode , it worked when screen is off or in background

5.Build the release version for TestFlight

6. Tested with release version, checked the working of alarm by keeping the iOS device screen off, it didn't play sound and when we reopen app it crashed

...

Expected behavior

We need to hear the sound in iOS when the app is idle for long time or in background

Attached screenshots for more details