MobileRTC Service nil

I am using zoom sdk in my ios 11.4.1. It was working fine when I released the app. But now after few days, its not working any more. I am getting nil on executing this - MobileRTC.shared().getMeetingService().
It has already been authorized in appDelegate successfully. But still getting service nil in my main view controller. Please help ASAP.

 

iOS SDK has switched into dynamic lib, so you should link SDK as embedded binaries. For more detail, you can refer to SDK example of the latest version on Github. Thank for choose zoom.