Hi mahmoud_arafa,

According to your description and screenshots, I suggest that you could check the following steps.

• Check if your connectstring is right.

1. Open the SQL Sever Object Explorer.
2. Find the Database you want to connect to and right click on it to find the Properties item.

Find the Connection string item in General settings and copy the string to Web.config.

  <connectionStrings>
    <add name="ConnectionStringName" connectionString="Paste the Connection string" providerName="System.Data.SqlClient"/>
  </connectionStrings>

• Check the settings in Sql Server Configuration Management

1. Open the Sql Server Configuration Management ( How to open )->SQL Server Network Configuration->Protocols for 'servername' and check TCP/IP is enabled
2. Open SSMS in run, and check you are able to login to server using specfied username/password and/or using windows authentication.
3. Repeat step 1 for SQL native client config also.

Best Regards,

Jenifer