OrganizationServiceProxy returns null

Hello, 

I'm trying to connect my console application to CRM but the OrganizationServiceProxy  returns null. 

I installed the latest version of Microsoft.CrmSdk.CoreTools and added relevant DLLs

Added the connection string - 

<add name="CRM" connectionString="Url=mtxopenuniversity.crm4.dynamics.com; Username:yoadb@mtxopenuniversity.onmicrosoft.com; Password:c.9@tHQC; AuthType=Office365"/>

But it still returns null as shown below -

What could be the problem here? I double checked Url, username and password of connection string .