The exception that is thrown when the domain server is not responding.
Assembly: Microsoft.SharePoint (in Microsoft.SharePoint.dll)
Use the exceptions in the Microsoft.SharePoint.EmailIntegration namespace to provide error handling to your implementation of the IEmailHelperService interface. All of the methods of that interface return a RequestStatus value, either by itself or as a member of a RequestResponse object. Consider catching exceptions and returning an appropriate RequestStatus value, such as ServerUnavailable.