Gravity Forms has an option to allow for file uploads. By default, this feature, when utilized by an end-user, will upload the file to an obfuscated URL by Gravity Forms.
When viewing the entry, either via email notification, or the ‘Entries’ page of Gravity Forms, the link to this URL will return a 500 error in some server cases.
Apache Resolution: Edit Apache config: to include a directive that matches:
<Directory /var/www> Options FollowSymLinks AllowOverride FileInfo Options <Directory>
Without the Options in the directive, Apache doesn’t allow access to the file-based URLs.