I'm trying to use SendMail in a custom module. Messages send fine as long as the TO address is within my own domain. Messages will not send, though, to any address outside the host domain. Exception reports mailbox does not exist. DNN version 5.4.2


AssemblyVersion: 5.4.2
PortalID: 1
PortalName: Beta Site
UserID: 1
UserName: host
ActiveTabID: 61
ActiveTabName: Dashboard
RawURL: /dashboard.aspx
AbsoluteURL: /Default.aspx
UserAgent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/531.22.7 (KHTML, like Gecko) Version/4.0.5 Safari/531.22.7
DefaultDataProvider: DotNetNuke.Data.SqlDataProvider, DotNetNuke.SqlDataProvider
ExceptionGUID: 60b0be6c-2418-44c7-af6a-469a3dbcc995
InnerException: Mailbox unavailable. The server response was: <c-walker@ti.com> No such user here
FileName: 
FileLineNumber: 0
FileColumnNumber: 0
Method: System.Net.Mail.SmtpTransport.SendMail
StackTrace: 
Message: System.Net.Mail.SmtpFailedRecipientException: Mailbox unavailable. The server response was: <c-walker@ti.com> No such user here 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, String ReplyTo, MailPriority Priority, String Subject, MailFormat BodyFormat, Encoding BodyEncoding, String Body, List`1 Attachments, String SMTPServer, String SMTPAuthentication, String SMTPUsername, String SMTPPassword, Boolean SMTPEnableSSL)

I was using the Host account email and password. My issue was the account I was using was a system account that didn't own a mailbox of it's own (because no one would ever check it). After enabling this account to have a mailbox with my hosting provider, messages sent to all addresses both inside and outside our domain. Thanks for the help. Issue is resolved.