Based on your logs, I can see that all failed sign-ups were due to attempts to use an email address that already exists in the Auth0 database.
You can filter logs using this short Lucene query syntax: type:fs
and you will see that all sign-up attempts are linked to an email bxxxxxy.plxxxxx@gmail.com, and a user with this email already exists in the “Username-Password-Authentication”. With this email, you can log in but not sign up.
Could you please test the sign-up with a different email address and let us know?