Site Works but can't use ADMIN or /wp-admin [solved]

Yesterday, the site was fine and I could log in using /wp-admin.

Today, I can get to the site and it loads. When I use /wp-admin, I’m getting redirected to:

The same thing happens when I used the Admin button in Local.

Here’s what I’ve tried to do with no success:

  1. Tried a different browser
  2. Cleared my browser cookies and cache
  3. Stopped and restarted the site and Local
  4. Edited the session token in the wp_usermeta tabel. (I saw this when Googling for a fix and it worked for some.)
  5. Checked error logs and access logs

Clearly I’m missing Step 6 which is the solution. Any ideas what that might be?

Thanks in advance.

[Update] I decided to take as a look at what files had recently changed. In doing so, I saw that my wp-login.php has been changed the day prior and was 0k. I grabbed a backup copy and restored. That solved the issue excpet for finding out why that file got to be 0k.