Admin cannot login…

This one puzzles me…

I have WordPress 4.2.2 with child-theme based on twenty-eleven theme. It’s been running just fine until couple of weeks ego. It still runs just fine, except the admin account cannot login to the site. Yes, I do know the password, thanks to Password Safe; the password did work until couple of weeks ego. After entering the admin credentials it displays the login screen again without any error message.

Using the “Lost your password?” link works and after requesting a new password, it shows the usual “Check your email…” message. The problem is that the email never comes. Other non-admin users have no issues with logging in to the site, they can reset the password and do receive the email.

I had one of the users login to the blog site using my internet connection IP and as luck would have it, she didn’t remember her password. She had reset the password, received the email, and logged in to the blog with no issues.

Following the guidance at this website, I’ve successfully created a new admin account utilizing phpMyAdmin for the database. Except this admin account cannot login either, nor do I receive the email for password reset. And yes, I did use a different email account for the new admin.

The user accounts shown by phpMyAdmin are accounted for; I actually know all of the account owners. This is a blog for not for profit organization with limited user account needs.

Reinstall WordPress and restore DB backup is an option, but I’d like to avoid it, if possible. Any suggestion how to restore admin login would be appreciated.
TIA…