Strange problem firebase login

Hello friends.

I’ve been looking for the solution to a problem with firebase for days.
When I call the Singin function in firebase, during the IF Not Error, it executes both options (if & else) that results in an alert in the else section, Curiously even though I change the title and the alert message is not change The correct part is also executed (if no error) this sends to the next screen, where everything works perfectly with firebase (read and write) but the alert still appears on the new screen,
I have noticed that if I delete the block of the alert it does not seem and that if I print the text of the error of the singin it indicates: Undefined.

Thanks to those who can help me


I’m ready posmoret your project if you give me a link to it and access to firebase in personal message. If you do not want to give it to me, then I can only recommend you to use step-through debugging, and check data in each bloks. Personally, I have never seen a situation so that in the If block simultaneously performed both sections.

hello thanks for answering
The connection to Firebase is really correct. always has been.
I don’t know exactly from what moment it started to fail, it could be with the last update. I have cleared the blocks step by step until I find where the alert message came from and the strange thing is that I run both parts at the same time.