Sorry DNN newby

I have just set up a new DNN site it seems to be running fine but all automated emails are failing. Looking in the event log I get the error:

AssemblyVersion: 04.05.01
UserName: host
ActiveTabID: 43
ActiveTabName: User Accounts
RawURL: /Admin/UserAccounts/tabid/43/ctl/Edit/mid/358/UserId/3/filter/None/currentpage/1/Default.aspx
AbsoluteURL: /Default.aspx
UserAgent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30)
DefaultDataProvider: DotNetNuke.Data.SqlDataProvider, DotNetNuke.SqlDataProvider
ExceptionGUID: b0f5ae39-89d2-4d96-b1f9-acc4f655d1f3
InnerException: Syntax error in parameters or arguments. The server response was: 5.7.1 This system is not configured to relay mail - if you are the owner of a mailbox at this server please ensure your mail client is configured for outgoing authentication in your account settings.
FileName:
FileLineNumber: 0
FileColumnNumber: 0
Method: System.Net.Mail.RecipientCommand.CheckResponse
StackTrace:
Message: System.Net.Mail.SmtpException: Syntax error in parameters or arguments. The server response was: 5.7.1 This system is not configured to relay mail - if you are the owner of a mailbox at this server please ensure your mail client is configured for outgoing authentication in your account settings. at System.Net.Mail.RecipientCommand.CheckResponse(SmtpStatusCode statusCode, String response) at System.Net.Mail.SmtpTransport.SendMail(MailAddress sender, MailAddressCollection recipients, String deliveryNotify, SmtpFailedRecipientException& exception) at System.Net.Mail.SmtpClient.Send(MailMessage message) at DotNetNuke.Services.Mail.Mail.SendMail(String MailFrom, String MailTo, String Cc, String Bcc, MailPriority Priority, String Subject, MailFormat BodyFormat, Encoding BodyEncoding, String Body, String Attachment, String SMTPServer, String SMTPAuthentication, String SMTPUsername, String SMTPPassword, Boolean SMTPEnableSSL)
Source:
Server Name: SODIUM

I have set the SMTP setting within the HOST settings, I have tried this with account details that can send fine from outlook etc, with and without usernames and passwords etc. Still no luck.

Have I missed something in setting up my DNN site, or do I need something else setting up?

Any help appreciated.

Thanks for the help.

The mail server worked fine for normal mail but all was being sent with one of my mail addresses so though all was fine. Having searched around I had come to the conclusion that it is mail server config blocking the sending of the messages as DNN is trying to send messages from other domains. Also the test mails were going OK just the registration mails were failing, as on a few other threads.

So looks like your correct I am on a shared hosted service so need to get the support guys to sort out so I can relay mails from other addresses I suppose. As a last resort I will end up trying a relaying service like DynDNS but want to see if I can get my host give me a relay service.