In the event lo the error is this:

InnerException: The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.7.1 Client was not authenticated

FileName:

FileLineNumber: 0

FileColumnNumber: 0

Method: System.Net.Mail.MailCommand.CheckResponse

StackTrace:

Message: System.Net.Mail.SmtpException: The SMTP server requires a secure connection or the client was not authenticated.

The server response was: 5.7.1 Client was not authenticated at System.Net.Mail.MailCommand.CheckResponse(SmtpStatusCode statusCode, String response) at System.Net.Mail.MailCommand.Send(SmtpConnection conn, Byte[] command, String from) 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)

Source:

Server Name: NAMEOFSERVER

It may be a certificate problem?

Thanks