diff --git a/config/defaults.inc.php b/config/defaults.inc.php
index 5fc3c0229..4a872d7b8 100644
--- a/config/defaults.inc.php
+++ b/config/defaults.inc.php
@@ -323,11 +323,11 @@ $config['smtp_timeout'] = 0;
 // The example below enables server certificate validation, and
 // requires 'smtp_timeout' to be non zero.
 // $config['smtp_conn_options'] = [
-//   'ssl'         => [
-//     'verify_peer'  => true,
-//     'verify_depth' => 3,
-//     'cafile'       => '/etc/openssl/certs/ca.crt',
-//   ],
+//     'ssl' => [
+//         'verify_peer'  => true,
+//         'verify_depth' => 3,
+//         'cafile'       => '/etc/openssl/certs/ca.crt',
+//     ],
 // ];
 // Note: These can be also specified as an array of options indexed by hostname
 $config['smtp_conn_options'] = null;
diff --git a/program/lib/Roundcube/rcube_imap_generic.php b/program/lib/Roundcube/rcube_imap_generic.php
index ab685a054..6468a00b2 100644
--- a/program/lib/Roundcube/rcube_imap_generic.php
+++ b/program/lib/Roundcube/rcube_imap_generic.php
@@ -1054,7 +1054,8 @@ class rcube_imap_generic
         }
 
         if (!empty($this->prefs['socket_options'])) {
-            $context  = stream_context_create($this->prefs['socket_options']);
+            $options  = array_intersect_key($this->prefs['socket_options'], ['ssl' => 1]);
+            $context  = stream_context_create($options);
             $this->fp = stream_socket_client($host . ':' . $port, $errno, $errstr,
                 $this->prefs['timeout'], STREAM_CLIENT_CONNECT, $context);
         }