Connection String issue on Server

Question

Hi,
I have created a web application in asp.net with SQL.I have mentioned ConnectionString in web.config as follows:

  <connectionStrings>
    <add name="xyzConnectionString" connectionString="Data Source=.\SQLEXPRESS; Initial Catalog=XYZ;Integrated Security=True;Trusted_Connection=No" providerName="System.Data.SqlClient"/>

    </connectionStrings>
But when i am uploading this webapplication on Parallels Plesk Panel Dedicated server and connect with database then i am getting an error as follows::

Server Error in '/' Application.

---

Login failed for user ''.

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: Login failed for user ''.

Please help me.
Thanks in advance.