Crossdomain policy trouble

I got such error
“System.Security.SecurityException: Unable to connect, as no valid crossdomain policy was found”
I try to connect to a localhost MS SQL database. I have literally no idea what to do, i tried to use Security.PrefetchSocketPolicy(“localhost”,1433)(as well as “127.0.0.1”) but it failed.
I really hope someone knows how to fix it,
PS.
Yes i have tried unity forum and answers to search for a solution.

You need a socket policy server to be running and listening on the socket you use in the Security.PrefetchSocketPolicy call. As the documentation says, there is an example server provided in the Unity installation folder. Get this running (on port 1433, or the default of 843). Then run your Unity code, and check the socket policy server log to see that it saw the connection.