Userids not registering

I’ve tried several times to add users from an admin userid. I click on “Add User,” click the “send an email with the password” check box, and click on Submit. Everything appears to go through no problem. However, in the next screen the just added id doesn’t show up in the list of users, the email never arrives in the user’s email, and the new userid doesn’t work. I’ve tried it over and over again over a couple of hours, always the same thing.