SQL Server is on the same machine. I can log in to the database server and access the database with the icogzimbra user id in SQL Server Management Studio just fine. Here is the entire error message:
Critical Error: SiteUrls.Config
Specific Error Message: The type initializer for 'Telligent.Evolution.Components.ApplicationSet' threw an exception. Cannot open database "Zimbra Icog" requested by the login. The login failed. Login failed for user 'IIS APPPOOL\icogzimbra'.
Please contact your site administrator. An explanation for why this error could occur is below.
Zimbra Community expects to find a valid XML file containing all of the links for a community. By default, this file is located at the root of the site and is named SiteUrls.config.
A common error is that SiteUrls.config included unescaped XML characters, such as "&" when defining a querystring.