In addition to this, due to some recent website hacks we had to secure our sites more. In doing so, we discovered that file_get_contents failed to work, where curl still would work.
Not 100%, but I believe that this php.ini setting may have been blocking the file_get_contents request.
; Disable allow_url_fopen for security reasons
allow_url_fopen = 0
Either way, our code now works with curl.