It sounds like you're experiencing an issue where an app stops working or a call is disconnected when your screen turns off while using speaker or Bluetooth. This is typically due to the battery optimization settings or other settings that restrict background activity on your phone. Here's how you might address the problem, depending on your phone's operating system:

For Android:

1. Battery Optimization Settings:

   • Go to "Settings" -> "Apps & notifications" -> "[Your app]" -> "Battery" -> "Battery optimization".
   • Find your app on the list, and select "Don't optimize".

2. App Permissions:

   • Go to "Settings" -> "Apps & notifications" -> "[Your app]" -> "Permissions".
   • Make sure that all necessary permissions are granted.

3. Background Activity:

   • Go to "Settings" -> "Apps & notifications" -> "[Your app]".
   • Find an option that refers to "Background activity" or "Background refresh" and ensure it's allowed.

For iOS:

1. Background App Refresh:

   • Go to "Settings" -> "[Your app]".
   • Ensure "Background App Refresh" is enabled.

2. Battery Settings:

   • Go to "Settings" -> "Battery".
   • Ensure "Low Power Mode" is off, as it may restrict background activity.

3. App Permissions:

   • Go to "Settings" -> "Privacy".
   • Ensure your app has all the necessary permissions enabled.