Webmail Error Connection timed out110 Can’t open SMTP stream.

Sometimes while sending the e-mails via webmail we are getting error as follows:

ERROR: Message not sent. Server replied: Connection timed out110 Can’t open SMTP stream.

Also when we login the webmail interface,It works well but when we compose the email and click on send email, the interface stuck.

The possible reason that the server firewall ( csf ) might be blocking the SMTP

For this we’ll need to check the csf configuration file /etc/csf/csf.conf
and check for the parameter “SMTP_BLOCK”

If it is set to

SMTP_BLOCK = “1”

It is enabled thereby it will block outgoing SMTP.

Please turn it to

SMTP_BLOCK = “O”.

And webmail will start working perfectly.