Email sending error: 550 Access denied – Invalid HELO name

An error message ‘550 Access denied – Invalid HELO name’ appears when sending email through outlook or other mail clients on exim / cPanel server. The message reads as follows:

Task ‘email address – Sending’ reported error (0x800CCC78): ‘Cannot send the message. Verify the email address in your account properties. The server responded: 550 Access denied – Invalid HELO name (See RFC2821’

Email Sending: 550 Access denied – Invalid HELO name

Email Sending: 550 Access denied – Invalid HELO name

After investigating the error message in exim mail server logs /var/log/exim_mainlog on the cPanel server, it was not clear why this error was being generated. How can a client send invalid HELO? They are using their own email account on the server. Google search did not help. Many cPanel users suggested disabling invalid HELO check in Exim Configuration. However disabling that will result in a lot of incoming spam from bots for all clients. User was just trying to send email through their account i.e. relaying it.

And that is the clue: Email Relay. Client was using old antirelayd system which relies on SMTP relay after IMAP/POP3 authentication. That old system is disabled to increase the security of the server. To relay email through the server requires SMTP authentication using the same login information as POP3/IMAP.

The following screen shot shows how to enable this in Microsoft Outlook. This is usually found under More Settings of an email account. Select the Outgoing Server tab and check the My outgoing server (SMTP) requires authentication. The first radio button will use same username/password combination used by incoming mail server (either POP3 or IMAP). This way you do not have to update it at two places when you change the email account password.

Outlook Email Settings: My outgoing server (SMTP) requires authentication

Outlook Email Settings – My outgoing server (SMTP) requires authentication

As soon as the SMTP authentication is activated, emails can be relayed from the server and there is no invalid HELO name error.


saeed on February 20, 2014  ·  Reply

Thanks for Good Answer

Akash Bhatnagaer on August 17, 2014  ·  Reply

Thanks for resolving my prb

Ahmad mourad on September 14, 2014  ·  Reply

Thank you Man

Nick on October 16, 2014  ·  Reply

Thanks this worked!! So simple!

Dude on November 15, 2014  ·  Reply

Thanks 🙂 It worked

brigitte on November 16, 2014  ·  Reply

thanks it work 🙂

ali on January 25, 2015  ·  Reply

Thanks !!! It worked

Davor Savic on January 29, 2015  ·  Reply

THX a lot. Solved my problem.

stefan d on February 13, 2015  ·  Reply

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Agnes M on February 15, 2015  ·  Reply

I’m dropping comment just to prove how it REALLY does SOLVE the problem
a post of almost a year ago still relevant to solve today’s problem. thank you!

Gab on April 6, 2015  ·  Reply

OMG Thankyou so much! just spend 2 hours trying to work it out until i googled this post. IT WORKED X

Karina on April 27, 2015  ·  Reply

THANK YOU SOOOO MUCH! It really worked!

Amanda on May 26, 2015  ·  Reply

Thank you, it worked for me. Such a simple thing to miss.

vijay on July 16, 2015  ·  Reply

Thanks a ton

Kunal on August 28, 2015  ·  Reply

Thanks….very helpful

manju Pendari on September 3, 2015  ·  Reply

Thank you for answer, It is working now

Aidyl on October 1, 2015  ·  Reply

Thank you, simple answer that saved me time!

DM on October 6, 2015  ·  Reply

Straight to the Point 100% Working quick solution !! Thanks !

Amit on October 6, 2015  ·  Reply

Thanx a lot

James on October 24, 2015  ·  Reply

Great piece of advice. Huge Thanks!

Catherine on October 14, 2020  ·  Reply

Thanks so much man, 5 years since this post helped someone and today it has come through for me. Thanks again

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