Login with custom field

Hi @grumpypjs08

You cannot log-in without a password as UM is preventing users from accessing other users account directly with a custom field or username/user_login. You will have to customize it and detach the UM validation so you can bypass it and allow users to login with a custom field.

You can try detaching that validation with the following code snippet:
remove_action( 'um_submit_form_errors_hook_login', 'um_submit_form_errors_hook_login', 10 );

Regards,