Users can’t reset password

Hello, I am experiencing some issues with login.
Some of the users who have a user account can’t reset their password when they want to book an appointment. It says “Resetting password is not permitted for this user” (translated from another language).

So I booked one of them manually, but she never got an email confirmation of the appointment sent to her e-mail. She already checked the spam folder, but nothing there. ??

How do I fix this, so all users can reset their passwords and get e-mail notifications?

Thanks.

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