I ran into some 500 internal errors when making a local mirror version of a site for dev. I am using version 5.7.5.6, and running on ampps locally for development. After exporting my production database, downloading the files, recreating a new database with same credentials, and uploading the files to the dev server, I kept getting a 500 error. After doing some research I looked into the apache logs and found the following error:
command 'suPHP_ConfigPath', perhaps misspelled or defined by a module not included in the server configuration

So this turned out to be a line in the .htaccess file in the install folder for C5. Commenting this out was the first step I needed to take. I also deleted the contents of files/cache. This was the first step, and the 500 error went away, but now I had a debug error page stating "Call to undefined function Doctrine\ORM\Query\ctype_alpha() ".

I found the fix here.
https://github.com/doctrine/doctrine2/issues/5364...
All that was needed was to enable the php5-mod-ctype package.

This now allowed me to see the site load successfully on my dev system. I now has issues with only the top and login pages loading, and had 404 errors for all other pages.

After more google searches, it appears that this was the pretty urls issue.
FOund the solution here:
https://www.concrete5.org/community/forums/5-7-discussion/5.7.5.2-pr...

Now my dev version of my site is running well.

Hope this helps someone!