SOLVED - Can't access admin after moving to a new server

Hello,

I have just transferred our Opencart store from 1and1 to Fasthosts as we now have a dedicated server package. I've managed to get the store up and running but I receive a HTTP ERROR 500 when I try and access the admin area.

I have updated the config.php files to point to the new location and have added the new database details. The store loads products just fine so I know the DB connection part is fine.

I have transferred the previously-working .htaccess file but also tried disabling it as well as adding the default version of it, too, but this makes no difference.

Any other clues would be gratefully received as I'm now pulling my hair out.

Thanks in advance.

So I've done some troubleshooting and enabled showing all errors which gave me some clues.

I now only have errors relating to VQMODs. Does anyone have any suggestions on how I can fix the following?

Warning: require_once(system/engine/controller.php): failed to open stream: No such file or directory in /home/XXXXX/public_html/vqmod/vqcache/vq2-system_startup.php on line 85

Fatal error: require_once(): Failed opening required 'system/engine/controller.php' (include_path='.:/opt/cpanel/ea-php56/root/usr/share/pear') in /home/XXXXX/public_html/vqmod/vqcache/vq2-system_startup.php on line 85

Never mind. Fix it myself. for anyone else that finds themselves in the same situation, create a file on your server called test_file.php containing the code:
Then view that file. Make sure the settings in both your config and admin/config file point to whatever destination appears.