roundcube: "Authentication failure: STARTTLS failed" when trying to send mail
Solution 1:
When you set $config['smtp_server'] with an URL that starts with tls://, you're setting up a PHP SSL context. As suggested by the default roundcube config, you may need to set options on the context.
In my case, I had to provide:
-
peer_name, the mail server's domain name. -
cafile, the CA file path.
You can put the following in your Roundcube config.inc.php file:
$config['smtp_conn_options'] = [
'ssl' => [
'peer_name' => 'mail.example.com',
'cafile' => '/etc/ssl/certs/ca-certificates.crt'
],
];