I run my app(the first page is CreateAccountViewController) and I got this logs
2017-10-16 11:59:54.939874+0800 MyApp[7876:225869] [Firebase/Analytics][I-ACS023007] Firebase Analytics v.40003000 started
2017-10-16 11:59:54.941076+0800 MyApp[7876:225869] [Firebase/Analytics][I-ACS023008] To enable debug logging set the following application argument: -FIRAnalyticsDebugEnabled (see http:/
2017-10-16 11:59:55.184432+0800 MyApp[7876:225749] [MC] Loaded MobileCoreServices.framework
2017-10-16 11:59:55.608120+0800 MyApp[7876:225877] Could not successfully update network info during initialization.
2017-10-16 11:59:55.671035+0800 MyApp[7876:225877] TIC Read Status [1:0x0]: 1:57
2017-10-16 11:59:55.671236+0800 MyApp[7876:225877] TIC Read Status [1:0x0]: 1:57
Then, there are three text fields on the page, Password, Email and Username and an image view. When I click SignUp button this two lines of logs are added
fatal error: unexpectedly found nil while unwrapping an Optional value
2017-10-16 12:00:03.364552+0800 MyApp[7876:225749] fatal error: unexpectedly found nil while unwrapping an Optional value
(lldb)
And the button disabled and whole screen stuck. What is happening? Anyone knows the solutions? I am using Firebase. Please help me . Thanks