When I run my swift 3.2 code with Xcode 9 beta 4 this is the error I get:
*** Terminating app due to uncaught exception \'com.firebase.core\', reason: \'[FIRAp
Actually this error is occur when GoogleService-Info.plist file is not actually located in our project folder but it just have a reference to that file where it is downloaded. So solution is that remove reference to this file and again add it to your project folder by drag and drop or by using "Add Files ..." option by right click to your project folder. Also recheck whether file is locating your project folder destination otherwise error will be occur again.
Don't forget to check your "GoogleService-Info.plist" file have same name as shown in error otherwise rename it.