Window: unrecognized selector sent to instance

Description
In the joinMeeting function I have created, I am running into an error when joinMeetingWithDictionary is called. The error I’m getting is a ‘window: unrecognized selector sent to instance’. The function I’ve created is here:

- (void) joinMeeting: (NSString*) meetingNo {
    if(![meetingNo length]){
        NSLog(@"meeting number not created");
        return;
    }else{
        MobileRTCMeetingService *service = [[MobileRTC sharedRTC] getMeetingService];
        NSLog(@"%@",service);

        if(service){
                    NSLog(@"Service created");
            
            service.delegate = self;
            NSLog(@"delegate set");
            NSDictionary *paramDict = @{
                kMeetingParam_Username: @"User",
                kMeetingParam_MeetingNumber: @"111111111",
                kMeetingParam_MeetingPassword: @"",
            };
            NSLog(@"Params set%@",paramDict);
            MobileRTCMeetError response = [service joinMeetingWithDictionary:paramDict];
            NSLog(@"onJoinMeeting, response: %d",response);
        }else{
            NSLog(@"Service not created");
        }
    }
}

It runs fine up until the line with ‘[service joinMeetingWithDictionary:paramDict];’ and results with an error:
-[GUL_AppDelegate-538C9E61-F7DA-41B7-AD94-8C36AC2513D1 window]: unrecognized selector sent to instance 0x6000035d0380

Which is a Thread 1: signal SIGABRT

I get the same error when using handZoomWebUrl with the zoom meeting web url.

Which version?
MobileRTC Version: 4.4.57220.1211

EDIT:
I also receive a warning for the line:

service.delegate = self;

The warning is:

Assigning to 'id<MobileRTCMeetingServiceDelegate> _Nullable' from incompatible type 'CallbackViewController *const __strong'

Hi daniel.brog,

Thanks for using Zoom SDK. Regarding the warning reason: '-[ GUL_AppDelegate-538C9E61-F7DA-41B7-AD94-8C36AC2513D1 window: unrecognized selector sent to instance, there is a chance that it might not relate to our SDK, please see the following links:

However, if you are experiencing a crash, could you provide the .crash file and the SDK log so we can further investigate and find out the root cause?

Thanks!