It seems that the recent WordPress 4.4 update got error when you update your script automatically.

When the WordPress updated, you will get blank page, and get the message:

SERVER ERROR 500

And it is simple to fix this problem,

just open your site with another browser, then you will get the following page:

wordpress update 4.4 error

Database Update Required

WordPress has been updated! Before we send you on your way, we have to update your database to the newest version.

The database update process may take a little while, so please be patient.

Just click the button and your site will be back!

Update Complete

Your WordPress database has been successfully updated!