I'm using Dotnetnuke CE 6.20...  I've configured the SMTP settings and did EMAIL test in Host settings. The host email account is receiving the email so the email functionality is working fine when I click on TEST email...

The SMTP email address password is correct otherwise TEST email should not work...

The Application is hosted at 3rd party hosting company... I've set for SMTP  server localhost, domain name was not working.. could this be the reason? but then the test email should also not work....

But when an user is registering or I'm adding/removing roles the email is not working (send notifiction is checked). I get an exception in Event log (LOG VIEWER).  And the message is :

Mailbox unavailable. The server response was: Delivery is not allowed to this address.

ANY IDEA where and what to check?????????

SEE BELOW for the detail of ERROR

AssemblyVersion: 6.2.0

PortalID: 0

PortalName: PortalXXXX

UserID: 1

UserName: host

ActiveTabID: 71

ActiveTabName: User Accounts

RawURL: /Admin/UserAccounts/tabid/71/ctl/Edit/mid/425/UserId/5/currentpage/1/Default.aspx?filter=Tümü&popUp=true

AbsoluteURL: /Default.aspx

AbsoluteURLReferrer: http://MYDOMAIN.com/Admin/UserAccount...

UserAgent: Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; Trident/5.0)

DefaultDataProvider: DotNetNuke.Data.SqlDataProvider, DotNetNuke.SqlDataProvider

ExceptionGUID: 3ad78f04-6822-461f-aaa2-9cf01c26231c

InnerException: Mailbox unavailable. The server response was: Delivery is not allowed to this address.

FileName:

FileLineNumber: 0

FileColumnNumber: 0

Method: System.Net.Mail.SmtpTransport.SendMail

StackTrace:

Message: System.Net.Mail.SmtpFailedRecipientException: Mailbox unavailable. The server response was: Delivery is not allowed to this address. 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.SendMailInternal(MailMessage mailMessage, String subject, String body, MailPriority priority, MailFormat bodyFormat, Encoding bodyEncoding, IEnumerable`1 attachments, String smtpServer, String smtpAuthentication, String smtpUsername, String smtpPassword, Boolean smtpEnableSSL)

Source:

server: serverxxxxxx

I didn't ask the hosting company since it's not a failure for them and even they are not responsible for the DNN app.  I've installed the DNN620 and SQL2008 DB on their hosting space. But I assuume they are not responsible for this kind of errors.

But why does the EMAIL test in Host settings work well and not for the "send notification" ?