App delegate error maybe fire base

What is this? Does anyone know how to solve it ?

I am pressing the sign up button and it directs me to the signup form. But when I press the login button it crashes with this error message

Thank you in advance!!!

Check that your segue to take you to the SignUpViewController is configured correctly. ie: it should be configured from the SignUpButton to the SignUpViewController and when creating it you should have selected 'Show" from the “Action Segue” list.
Ensure that your SignUpViewController in storyboard has the custom class set to SignUpViewController.