When you access your MSSQL database through MSSQL Server Eeterprise Manager from Parallels Plesk Control Panel or a web browser you get following error.
"405 - HTTP verb used to access this page is not allowed.
The page you are looking for cannot be displayed because an invalid method (HTTP verb) was used to attempt access."
1. Enter into %plesk_bin% directory.
2. Execute the command 'defpackagemng --fix --type=sqladminmssql '
If above solution does not work change the application pool for 'mssql' to 'DefaultAppPool' that is set to 'integrated' mode. And then try the above solution again.