iOS incomingCall.reject on background mode doesn't notify caller

[hyunoosung]

Describe the bug Reject call on background doesn't notify caller where rejecting in foreground successfully notify rejected state to caller.

To Reproduce Steps to reproduce the behavior:

1. Caller calls to iOS app
2. iOS user rejects call in lock screen
3. Caller is still ringing even though iOS app has successfully rejected the incoming call.
4. Above scenario works ok on foreground and I can see the event on console as below

CallClient1:CallAgent1:Call:ad152d9b-9109-4a6a-8d37-662085b79eea:Ringing Call end reason=Declined, code=603, subCode=0

But when incoming call is rejected from background or lock screen, caller doesn't get the declined event. 5. When caller hangs up while iOS app is ringing, it properly notifies didEnd incomingCall delegate and works properly on iOS side.

Expected behavior Caller gets declined event when Callee reject from lock screen or background so that Caller doesn't have to wait until timeout.

Screenshots If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: BigSir
• Browser Chrome
• Version 90.0.4430.93

Smartphone (please complete the following information):

• Device: iPhone SE2
• OS: 14.0

[raosanat]

@hyounoo in background if you are rejecting you are doing through CallKit, can you please send us the .blog files to investigate further. Also if you can test on latest beta version of the SDK and use the CallKit integration in the SDK, do you still see the issue ?

[mariusu-msft]

@hyounoo can you share a code snippet on how you are ending the call?