Login issues on RNVApp

Hi everyone, I’m implementing my first app. I have created a registration \ login system through Firebase Auth. I notice a very strange thing:
after creating a user (all data has been correctly saved on Firebase), if I try to login from the Web Preview or from my phone, the login works. If, on the other hand, I try to do the same thing from the simulator on my Mac then I get an error of Wrong Username \ Password. I use a very simple password (1234) so there is no possibility of error. Anyone have any idea what the cause of this might be? Thank you very much!