The most common cause of 500 errors after transferring to Plesk is having Options in your .htaccess. You can try renaming your .htaccess file temporarily to see if the 500 error goes away. If the Options lines are the problem you can comment them out. We plan on enabling full support for Options in .htaccess eventually. You can also go to Login > Continue to Plesk > Websites & Domains > drroshan.ayur.heliohost.org > Logs. There it will list the exact reason for the 500 error. Let us know if you need further assistance.