Some kinda crazy email error

1

We cannot send invoices out by email today. This is the error we get. Help!

System.Net.Mail.SmtpException: System.Net.Mail.SmtpException: Mailbox unavailable. The server response was: Access denied - Invalid HELO name (See RFC2821 4.1.1.1)
at System.Net.Mail.MailCommand.CheckResponse(SmtpStatusCode statusCode, String response)
at System.Net.Mail.MailCommand.Send(SmtpConnection conn, Byte command, MailAddress from, Boolean allowUnicode)
at System.Net.Mail.SmtpTransport.SendMail(MailAddress sender, MailAddressCollection recipients, String deliveryNotify, Boolean allowUnicode, SmtpFailedRecipientException& exception)
at System.Net.Mail.SmtpClient.Send(MailMessage message)
at ManagerServer.HttpHandlers.Businesses.Business.Email.Post()

2

Hi there,
Firstly I have managed to fix the basic problem. Host server upgrade couple days ago. Needed to change from port 25 to port 587 and now sending ok.
However, secondly the text below from the host website recommends using a set of SSL settings which require port 486 which is not an option allowed in Manager. This means we cannot use the SSL method of sending emails and must use the NON-SSL method. Less than ideal and maybe something to add to the list of improvements for the future.

Secure SSL/TLS Settings (Recommended)
Username: email address
Password: Use the email account’s password.
Incoming Server: mail.website
IMAP Port: 993 POP3 Port: 995
Outgoing Server: mail.website
SMTP Port: 465
IMAP, POP3, and SMTP require authentication.
Non-SSL Settings (NOT Recommended)
Username: email address
Password: Use the email account’s password.
Incoming Server: mail.website
IMAP Port: 143 POP3 Port: 110
Outgoing Server: mail.website
SMTP Port: 587
IMAP, POP3, and SMTP require authentication.

3

Port 587 is standard for sending emails. It is insecure protocol but can be upgraded to secure protocol. Manager assumes the connection can be upgraded to be secure before sending any sensitive data. Otherwise email submission will fail. This would explain why port 587 doesn’t work for you.

I suggest use email provider who supports 587 port properly.