First time voice call not working in iOS/Android

When do first time voice call on receiver side call receive method not call. After restart the app thats working.

So can any one help on same.

Hey @vaquib.chauhan,

If the receiver has not authenticated yet then on the first time they will not be able to get the call. This is because both users need to have authenticated at least once before they can receive a call.

can you update voip notification certificate and try??

  1.  [Callee is offline] You have enabled push notifications on the Sendbird dashboard in the Settings > Notifications > APNs section.
  2.  Your .p12 certificate is not expired.
  3.  Your .p12 certificate is correctly mapped to “Incoming Call” for VoIP notifications or is correctly mapped to “Alerts” for incoming calls through remote notifications. A “Apple Push Notification service (Sandbox & Production)” or ‘VoIP Services Certificate” are the valid certificate types for accepting VoIP notifications. Only the “Apple Push Notification service (Sandbox & Production)” certificate is valid for accepting “Alerts”. 
  4.  Your .p12 certificate is correctly mapped to your development app or your production app. When the certificate is uploaded, you must specify ‘development’ or ‘production’ as the certificate type. 

Try this steps:)

I’m having this exact issue (can’t receive calls initially) on iOS though I haven’t verified that restarting the app helps. However, if I make a call first, then the corresponding delegates (didStartRinging, etc) are called and calls can be received and accepted. To @Alex_Preston 's point, I’m pretty sure that the receiver is authenticated, especially since making a call works. We’re trying not to use CallKit or PushKit at the moment if we can avoid it. Thanks.