Issue with WebRTC outgoing call (iOS,Kurento)

I'm fairly new to webrtc, and quite experienced in iOS.

We have a media server setup on AWS (all ports open), with kurento one2one client. Everything is working well when I call from desktop to desktop. when I call from desktop to iOS it works (i.e. incoming calls to iOS).

Issue is when I make an outgoing call from iOS to desktop, it doesn't work.

Below are the server logs, so I think call is getting connected...

Received message: {"id":"incomingCall","from":"qqq"}

spec: {"audio":true,"video":{"width":640,"framerate":15}}

chrome: {"audio":true,"video":{"optional":[{"minWidth":640},{"maxWidth":640},{"minFramerate":15},{"maxFramerate":15}]}}

Sending message:{"id":"incomingCallResponse","from":"qqq","callResponse":"accept","sdpOffer”:”huge text, so removed”}

Received message: {"id":"startCommunication","sdpAnswer":"huge text, so removed”}

When call is clicked I'm doing below on iOS:

[peerConnection offerForConstraints:[self defaultOfferConstraints] completionHandler:^(RTCSessionDescription * _Nullable sdp, NSError * _Nullable error) {
    
    [peerConnection setLocalDescription:sdp completionHandler:^(NSError * _Nullable error) {
        NSLog(@"%@",error.description);
    }];
    
    
    [[NSOperationQueue mainQueue] addOperationWithBlock:^ {
        NSDictionary *registerMessage = @{
                                          @"id": @"call",
                                          @"from": @"qqq",
                                          @"to": @"www",
                                          @"sdpOffer" : sdp.description,
                                          };
        NSData *messageData = [NSJSONSerialization dataWithJSONObject:registerMessage
                                                              options:NSJSONWritingPrettyPrinted
                                                                error:nil];
        NSString *messageString =
        [[NSString alloc] initWithData:messageData encoding:NSUTF8StringEncoding];
        [webSocket send:messageString];
    }];
}];

and after I get accept response I do below,

if ([answerID isEqualToString:@"callResponse"]) {
    NSString *answerRespose = [wssMessage objectForKey:@"response"];
    if ([answerRespose isEqualToString:@"accepted"]) {
        description = [[RTCSessionDescription alloc] initWithType:RTCSdpTypeAnswer sdp:sdpAnswer];
        [peerConnection setRemoteDescription:description completionHandler:^(NSError * _Nullable error) {
            
        }];
    }
}

I'm also taking care of ICECandidates...

As incoming works without any issue, I'm assuming that no mistake was made in creating stream. Am I missing something for outgoing call?

I finally found it out. Issue was with ICECandidates, I came to know that adding ICECandidate after setting remote description works. Made an array ICECandidates collected from web socket and added them once I got remote RemoteDescription :)

I hope this helps someone in future.