You could not connect MSSQL database in your windows system, need to set authentication for user,

Server Error in '/' Application.

Cannot open database "database" requested by the login. The login failed.
Login failed for user 'NT AUTHORITY\IUSR'.
Description: An unhandled exception occurred during the execution of the
current web request. Please review the stack trace for more information about
the error and where it originated in the code.

Exception Details: System.Data.SqlClient.SqlException: Cannot open database
"database" requested by the login. The login failed.
Login failed for user 'NT AUTHORITY\IUSR'.

Give permission anonymous account on the network by using IIS Manager:

Open the IIS Manager , search "INetMgr.exe" then press Enter,

Click on "Sites" -> Right click on specific "domain name",

Go to "Manage Website" -> "Advanced Settings..."



On Advanced Settings, Click on "Physical Path Credentials" Select User 




Choose on "Specific User", then click on "Set..."




Set Credentials, Give user name and password,



Click on "Ok" 



Click on "Ok"