Please turn on SMTP Authentication

[s.isselmou]

We have a local server on which a web application is installed, this server is supposed to send mails from a mail whose SMTP is hosted at a hosting provider, but sends it fails.
Initially, the server sends the following error message:
550 Access denied - Invalid HELO name (See RFC2821 4.1.1.1)
But we have disabled the "Require RFC-compliant HELO" option and we succeeded in sending emails but only to mails that belongs to the same domain.
For other destinations (eg GMAIL) the sending fails, the error message has changed and the server now sends the following message:
550-Please turn on SMTP Authentication in your mail client
Then we added the ip address of our local server in the SPF of the SMTP server but it did not work.
Thank you for helping us resolve this issue

 

[Jcats]

Try disabling SMTP Tweak:

WHM > SMTP Restrictions > Disable

 

[s.isselmou]

Hello,
First of all, thank you for your reply.
If we disable this option, our server will be less secure?
If this solution does not work, it is easy to return to the initial state? And how?

Thank you in advance.

Best regards

 

[Jcats]

Yes its easy, just click Enable. This is to test to see if that's the cause.

 

[s.isselmou]

I make your proposal but unfortunately nothing to change always the same problem

 

[cPanelMichael]

Hello,

Can you confirm the script you are using to send email is using SMTP Authentication to send the email? For instance, have you created an email account through cPanel and then configured the email account username and password in the script's configuration file or setup page? Also, do you have any firewall management applications such as CSF installed on the server?

Thank you.

 

[s.isselmou]

After testing on the outlook client we noticed that the sending of emails works well if we use the configuration SSL (port 465), but it does not work when we use the parameters non-SSL (prot 25) Which is abnormal.
Sending mail using the SMTP server with non-SSL settings is paramount for the operation of our application because it uses the default port 25.
We have a VPS server that uses WHM / Cpanel.
How to see on our server that the firewall is active or not
thank you.

 

[Jcats]

Go into WHM and scroll down to the bottom of the list on the left under Plugins it will say:

"ConfigServer Security & Firewall"

 

[cPanelMichael]

Sending mail using the SMTP server with non-SSL settings is paramount for the operation of our application because it uses the default port 25.

You can disable the following option under the "Security" tab in "WHM >> Exim Configuration >> Basic Editor" if you want to allow non-SSL authentications:

"Require clients to connect with SSL or issue the STARTTLS command before they are allowed to authenticate with the server."

Note that disabling this option will significantly decrease the security of the server by allowing the plaintext transmission of authentication credentials. Ideally, you would modify the script or consult with the developer so that it uses SSL when authenticating.

Thank you.

 

[s.isselmou]

Hello Michael
We have disabled the option is it works, the problem has been solved infinitely thank you.
also thanks Jcats.