App goes to deadlock when pause vuforia

Hi, I am struggling to use Vuforia for image detection. The problem occurs when i call pauseAR method to pause the vuforia and the app goes to deadlock. Below i'm attaching the log file as well as corresponding methods. Please let me know what should i do ? Thanks.

- (void) pauseAR {    NSError * error = nil;    if (![vapp pauseAR:&error]) {        NSLog(@"Error pausing AR:%@", [error description]);    }}

- (void)renderFrameVuforia{    [self setFramebuffer];

     .................................      

     .................................

     if (!strcmp(trackable.getName(), "steering_wheel_right_3")) {         [self pauseAR];

     }                     .................................      

   .................................

       Vuforia::Renderer::getInstance().end();    [self presentFramebuffer];}