I agree with the previous replies that this error is related to the email settings. Please check all of them one more time, especially because you use the Microsoft Exchange email address. You can start with this:
after oppening the Port I get thise Error: (confused)
'The server has rejected the sender address. The server answer is: 530 5.7.57 SMTP; Client was not authenticated to send anonymous mail during MAIL FROM [AM3PR07CA0054.eurprd07.prod.outlook.com] '
but I can send mail with other Programs
Update, Now I get this Error:
Error: SMTP protocol error. 530 5.7.0 Must issue a STARTTLS command first. Failed to send messageConnecting to mail server.
Maybe sombody have Idee
Something that sounds quite similair was asked and replied here locally. The problem was with the .Net SMTP client code for gmail, but maybe the same case exists for Microsoft as well.
I have an issue when trying to send an email from a customer’s email account from G Suite.
I receive an exceptions with the following message returned:
“System.Net.Mail.SmtpException: The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.7.0 Authentication Required. Learn more at”
Yes, the message end abruptly for some reason.
The issue was resolved.
The reason of access deny was that app-specific passwords work only when two-factor authentication is enabled, and for this account two-factor authentication was disabled today some time ago. So, my app password was not valid anymore.
@AlexKarasHi and thanks for your Reply.
in my case, that appear because the Hosting department blockiert the port 25. Now the port is open.
I can send mail with other program but just with TC, I get this error. :-(
After days and days, I have find a solution for this problem.
The CDO do not support TLS therefor this problem apear in my Case. I use another codes from this Link
maybe that is better to attache that codes in TC's help. :-)
Thanks for your investigation!
I'm sure the solution you've found will help many users. Thanks for sharing it.