Sometimes while sending email from Horde, it takes long time to load and at the end it shows the error message given below.
Horde error :Failed to set sender: email@example.com [SMTP: Failed to write to socket: not connected (code: -1, response: )]
Given below are the two parameters in CSF configuration file (/etc/csf/csf.conf) that should be checked.
1. Ensure that “SMTP_ALLOWLOCAL” is enabled in CSF configuration file. It should be enabled if you want to allow local connections to port 25 on the server (e.g. for webmail or web scripts).
SMTP_ALLOWLOCAL = “1”
2. Ensure that “SMTP_ALLOWLOCAL” has the value “1”.
If these options are not enabled, enable them and restart CSF using the command given below.