Need to Open Port to use SMTP in DirectAdmin? Or do I need to change something to use SMTP in DirectAdmin?
I went to add Mail Baby Mail Relay to my WHMCS website, (my whmcs is hosted with a VPS with DirectAdmin installed) and I get an error. (See screenshot)

I told mail baby customer support about this. He said that there is no problem with my Mail Relay.
Previously, I added this Mail Relay to the website in this way in Cpanel and Hestiacp Panel without any problem. I did not get such an error
I got the same error when trying to add Mail Relay to a Wordpress website on my VPS.
Is SMTP blocked by the firewall? Can you help me with this problem?
I went to add Mail Baby Mail Relay to my WHMCS website, (my whmcs is hosted with a VPS with DirectAdmin installed) and I get an error. (See screenshot)

Validation Error: SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting
I told mail baby customer support about this. He said that there is no problem with my Mail Relay.
Previously, I added this Mail Relay to the website in this way in Cpanel and Hestiacp Panel without any problem. I did not get such an error
I got the same error when trying to add Mail Relay to a Wordpress website on my VPS.
Is SMTP blocked by the firewall? Can you help me with this problem?