Green screen while pushing view controller

i have a login screen view controller (nib), when user logs in it instantiates storyboard and pushes initial view controller, but while transitioning to this initial vc there is green screen, when transition done main screen appears normally. ![enter image description here][1]

DMapViewController *mapVC = [[UIStoryboard storyboardWithName:@"DMapViewController"
                                                       bundle:nil] instantiateInitialViewController];
[self.navigationController pushViewController:mapVC
                                     animated:YES];

Copyright Notice：Content Author:「Anton」，Reproduced under the CC 4.0 BY-SA copyright license with a link to the original source and this disclaimer.
Link to original article：https://stackoverflow.com/questions/30766629/green-screen-while-pushing-view-controller