I created a blank project, visualization, and user matching your settings. However, I’m not able to replicate your error. I would suggest re-typing the password in the User configuration to ensure that it actually is set as “1234”.
I’ve attached my test project in case it helps you.
I don’t think that is possible. User management functions (such as displaying the user list) are only available to users with Administrator roles (as configured in the MpUserX Configuration). This is documented in the Online Help.