Windows Service Error

This code is in a timer in a windows service. The service installs successfuly and starts. I tested the code on a web form and it worked. Now when it runs in the service it errors out. From what I can tell it errors out on "Cnn.Open()". Other than that I don't know. The app settings are correct. the connection string is the used on a web app and works, so I don't see why it wouldn't work here.

These are the imported namespaces:
1. Imports System.ServiceProcess
2. Imports System.Data.SqlClient
3. Imports System.Configuration
4. Imports System.Web.Mail.SmtpMail
5. Imports System.DirectoryServices

Thanks for your assistance

Code:

---

Private Sub Timer_Elapsed(ByVal sender As System.Object, ByVal e As System.Timers.ElapsedEventArgs) Handles Timer.Elapsed
        Dim Cnn As New SqlConnection(ConfigurationSettings.AppSettings("Cnn"))
        Dim cmdCheck As New SqlCommand()
        Dim rdrCheck As SqlDataReader
        Dim DirEntry As New DirectoryEntry(ConfigurationSettings.AppSettings("ad"), ConfigurationSettings.AppSettings("admin"), ConfigurationSettings.AppSettings("pw"))
        Dim GroupSearch As New DirectorySearcher(DirEntry)
        Dim EmailSearch As New DirectorySearcher(DirEntry)
        Dim GroupResult, EmailResult As SearchResult
        Dim EmailList As New ArrayList()
        Dim X As Integer
        Dim BodyText As String

        Try
            SmtpServer = "W2KExchange" 'specify email server
            EmailSearch.PropertiesToLoad.Add("Mail") 'select email address for user search
            GroupSearch.PropertiesToLoad.Add("member") 'select users for the group search
            GroupSearch.Filter = ("(CN=Satellite Email Notification)")
            GroupResult = GroupSearch.FindOne
            For X = 0 To GroupResult.Properties("member").Count - 1 'select each users email address and enter it into an array
                EmailSearch.Filter = ("(" & Left(GroupResult.Properties("member").Item(X), InStr(GroupResult.Properties("member").Item(X), ",") - 1) & ")")
                EmailResult = EmailSearch.FindOne
                EmailList.Add(EmailResult.Properties("Mail").Item(0))
            Next
        Catch
            'email dba that the active directory search errored
            NotifyAdmin("Error searching Acitve Directory at " & Date.Now, EventLogEntryType.Error)
        Finally
            DirEntry.Dispose()
            GroupSearch.Dispose()
            EmailSearch.Dispose()
            DirEntry = Nothing
            GroupSearch = Nothing
            EmailSearch = Nothing
        End Try

        Try 'attempt to run a stored procedure and email users
            With cmdCheck 'check to see if there are any feeds in the next 45 mintues
                .CommandType = CommandType.StoredProcedure
                .CommandText = "sp_CheckForFeeds_s"
                .Parameters.Add("@DateTime", SqlDbType.DateTime, 20).Value = Date.Now
                .CommandTimeout = 30
                .Connection = Cnn
            End With
            Cnn.Open()
            rdrCheck = cmdCheck.ExecuteReader
            While rdrCheck.Read 'send an email for each feed in the reader
                BodyText = "Feed Time: " & rdrCheck.Item("FeedTime") & ", Signal: " & rdrCheck.Item("Signal") & ", Satellite: " & rdrCheck.Item("Satellite") & ", Sent: " & Date.Now
                For X = 0 To EmailList.Count - 1
                    Send(ConfigurationSettings.AppSettings("EmailFrom"), EmailList.Item(X), "Feed Notification", BodyText)
                Next
            End While
            rdrCheck.Close()
            Cnn.Close()
        Catch 'attempt failed
            'email dba that the stored procedure and email errored
            NotifyAdmin("Error quering database and emailing staff at " & Date.Now, EventLogEntryType.Error)
        Finally
            Cnn.Dispose()
            cmdCheck.Dispose()
            Cnn = Nothing
            cmdCheck = Nothing
        End Try
    End Sub

---

If you are using Windows security in your connection string remember that there is no user for a service so the login may fail, also it could be some sort of permissions error. What error are you getting?

Thanks for the insight, it would make sense that the account running the service needs access to the database.