Unable to connect to sql db with db owner rights via httpmodule registered in sharepoint web application !!

Hello,

I have registered module and connection string in SharePoint 2013 Web.config file.

<connectionStrings> 

   <addname="ConStr"connectionString="Application Name=Newsletter_APP_LOGS;data source=SP2013\SHAREPOINT;initial catalog=SPappDB;integrated security=False;User Id=SP2013\diptik;Password=spapp@123;Persist Security Info=True;Trusted_Connection=True"providerName="System.Data.EntityClient"  />

  </connectionStrings>

When I debug httpmodule class it throws following error:

Additional information: Cannot open database "SPappDB" requested by the login. The login failed.

 Note :

1. I am running app under user SP2013\diptik
2. User SP2013\diptik is having DBOwner rights onSPappDB database

Issue : - Why SP2013\diptik with DB owner rights is unable to connect to database ?

Thanks and Regards,

Dipti Chhatrapati