It's most likely because your server is not properly configured for sending emails. You'll need to either configure it properly or use some external SMTP server. More info on email configuration can be found here: https://milos.support-hub.io/articles/vanguard-configuration#email-configuration
I have a problem with the user registration, when I submit the form it gives an error 500 and the user does not register.
The same problem happens when a user uses the password reset form.
ErrorException: Trying to get property 'id' of non-object