Please could someone in the DNN incorporate this change into the next release? All I've done is check if _portalSettings.Email isn't null and there actually is a "@" in the address before trying to access the domain part of it in a substring.

It broke my DNN (4.4.1) install because I'd removed (silly me) the portal's email address. Gave up trrying to figure out what to edit in the database and just attached a debug version.

DotNetNuke.Library -> Components -> Authenitcation -> Configuration.vb

        Public Shared ReadOnly Property DefaultEmailDomain() As String
            Get
                Dim _portalSettings As PortalSettings = PortalController.GetCurrentPortalSettings
                Dim _portalEmail As String = _portalSettings.Email
                If (Not (_portalEmail Is Nothing) And _portalEmail.IndexOf("@") > 0) Then
                    _portalEmail = _portalEmail.Substring(_portalEmail.IndexOf("@"))
                End If
                Return _portalEmail
            End Get
        End Property