On the clients UAT environment. We can do the following.

• We can create umbraco users
• We can add items to the media library
• We can add forms.

However when we try and save content we see the following in umbracolog.

2017-01-16 17:27:37,845 [P2668/D2/T20] ERROR Umbraco.Web.Strategies.ServerRegistrationEventHandler - Failed to update server record in database. System.Data.SqlClient.SqlException (0x80131904): Cannot open database "MyDB" requested by the login. The login failed. Login failed for user 'domain\hostname1$'.

 <add name="umbracoDbDSN" connectionString="server=localhost;database=MyDB;Integrated Security=SSPI" providerName="System.Data.SqlClient" /> 

and

<authentication mode="Windows" />
    <identity impersonate="true" userName="corp\Umbraco-Service" password="password" />