Receiving error when trying to send email message through the CRM 2015 Email Router
ERROR: #61042 - An error occurred while processing the outgoing email message with subject "TEST CRM:0001001" for SMTP: http://<server>:5555/<org>for delivery through mail.corporate.com. System.Net.Mail.SmtpFailedRecipientException: Mailbox unavailable. The server response was: 5.7.1 Unable to relay
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 Microsoft.Crm.Tools.Email.Providers.SmtpPollingSendEmailProvider.ProcessMessageInternal(Entity emailMessage)
at Microsoft.Crm.Tools.Email.Providers.CrmPollingSendEmailProvider.Run()
we have used : Microsoft Exchange Server MAPI Client and Collaboration Data Objects 1.2.1
Please help...