It seems like you're experiencing some browser hiccups, Verapregoli. Let's get this fixed.
Good work for logging in using a private browser. It helped me know it's a web issue. Since you're able to sign in successfully through an incognito window, let's go back to the regular browser, then clear its cache. It prevents and fixes issues like this.
On the other hand, you can use a different web browser like Google Chrome or Mozilla Firefox.
Let me add this article on how to get help if you can't sign in to your account as a future reference.
Swing by if you need more of our help. We're just right here for you.