Flutter Background Service Bug Fix

I'm seeking an experienced Flutter developer to fix a background service issue in my app.

The problem:
- The app has two APKs: one for the healer and another for the user.
- Calls are initiated by the user using the Agora API.
- When the healer app is minimized or not running in the background, it fails to receive call notifications.

Your task:
- Fix this bug so that the healer app gets notified even when it is minimized or not running in the background.

Additional Information:
- Only remote work is possible via AnyDesk.
- The APKs need to support Android only.
- There are no specific error messages or logs when the healer app fails to receive the call notification; it simply doesn’t receive them.

Ideal skills:
- Proficient in Flutter development
- Experience with background services in mobile apps
- Familiarity with Agora API
- Problem-solving skills to troubleshoot and fix the issue

Please place your bid if you are confident in resolving this issue.