What I was after
Recently, I was trying to access the WordPress Dashboard of a site I hadn’t worked on in a while. Unfortunately, while the main site was working, I got a 500 error when trying to reach the Dashboard or Admin area of the site. My goal was to regain access without losing anything in the process.
There were some interesting resources on the 500 error as it relates to WordPress, but none of them actually had a solution that worked for me (I tried manually upgrading my version of WordPress, removing the Plugins, and Deleting the .htaccess file to no avail).
The important bits
In my case, the site was using an older version of WordPress (4.3.16) but I was running a recent version of PHP on my host (7.1). Temporarily changing my PHP version down to 5.5 allowed me to regain access to the WordPress Dashboard of the site. I upgraded the site to the latest version of WordPress through the Dashboard, updated my plugins, and then switched by PHP version back to 7.1 and have been able to maintain Dashboard access.
Strange that manually upgrading the WordPress version to the most recent release through FTP didn’t fix it and that it had to be upgraded when the PHP version was set to the older version, but this is what fixed it and everything is accessible now, so I’m not complaining and I hope this weird experience helps someone else in the same boat.