After upgrading to MODX 2.6.5 why does the Manager login page throw a 500 error?

I've upgraded to MODX 2.6.5 after being hacked and now I'm not able to login. And I don't mean that I try logging in and receive a 500 error. I mean when I simply visit http://mydomain.com/manager the login page doesn't load and instead generates a 500 error. All of my other upgrades went smoothly. I've also emptied the dashboard widget placement table and cleared the cache but still no progress.

Does anyone have experience.solution for this?

Thanks!
Jeff

Have you checked your server's error log? Not the MODX error log, but the server error log. You'll probably find an indication there.

PHP 7.x is much more likely that earlier versions to throw a 500 error when it hits a PHP error that earlier versions would pass.

One common culprit involves not having php-mbstring installed.

https://stackoverflow.com/questions/21699774/internal-server-error-http-error-500-after-installing-phpmyadmin-on-a-certain.

Turning on display errors might give you a clue: https://stackoverflow.com/questions/5680831/php-does-not-display-error-messages/5680885#5680885