diff --git a/lib/CleantalkSP/Common/RemoteCalls.php b/lib/CleantalkSP/Common/RemoteCalls.php
index 7f59fb7ab..678fe3659 100644
--- a/lib/CleantalkSP/Common/RemoteCalls.php
+++ b/lib/CleantalkSP/Common/RemoteCalls.php
@@ -35,6 +35,17 @@ class RemoteCalls
 
     const COOLDOWN = 10;
 
+    /**
+     * Timeout (seconds) for RC self-test requests.
+     * Keep low: expected response is immediate "OK".
+     */
+    const TEST_REQUEST_TIMEOUT = 7;
+
+    /**
+     * How many times to attempt RC self-test before giving up.
+     */
+    const TEST_REQUEST_ATTEMPTS = 3;
+
     /**
      * Checking if the current request is the Remote Call
      *
@@ -211,40 +222,51 @@ public static function performTest($host, $params, $patterns = array())
     {
         // Delete async pattern to get the result in this process
         $key = array_search('async', $patterns, true);
-        if ($key) {
+        if ($key !== false) {
             unset($patterns[$key]);
         }
 
         // Adding test flag
         $params = array_merge($params, array('test' => 'test'));
 
-        // Perform test request
-        $http   = new \CleantalkSP\Common\HTTP\Request();
-        $result = $http
-            ->setUrl($host)
-            ->setData($params)
-            ->setPresets($patterns)
-            ->request();
-
         $error_template = 'WRONG_SITE_RESPONSE TEST_ACTION FOR RC %s, ERROR: %s';
+        $error  = null;
+
+        for ($attempt = 1; $attempt <= self::TEST_REQUEST_ATTEMPTS; $attempt++) {
+            $error = null;
+
+            $http   = new \CleantalkSP\Common\HTTP\Request();
+            $options = defined('CURLOPT_TIMEOUT')
+                ? array(CURLOPT_TIMEOUT => self::TEST_REQUEST_TIMEOUT)
+                : array('timeout' => self::TEST_REQUEST_TIMEOUT);
+            $result = $http
+                ->setUrl($host)
+                ->setData($params)
+                ->setPresets($patterns)
+                // Prefer CURLOPT_* int keys: string 'timeout' is left in options by Request
+                // converter and breaks curl_setopt_array() on PHP 8+. Fallback to string
+                // name only when cURL constants are unavailable (no cURL extension).
+                ->setOptions($options)
+                ->request();
+
+            // Considering empty response as error
+            if ($result === '') {
+                $error = sprintf($error_template, $params['spbc_remote_call_action'], 'EMPTY RESPONSE');
+            // Wrap and pass error
+            } elseif (is_array($result) && ! empty($result['error'])) {
+                $error = sprintf($error_template, $params['spbc_remote_call_action'], $result['error']);
+                // Expects 'OK' string as good response otherwise - error
+            } elseif (is_string($result) && ! preg_match('@^.*?OK$@', $result)) {
+                $unexpected_response = 'UNEXPECTED RESPONSE: "' . json_encode(substr($result, 0, 400)) . '"';
+                $error = sprintf($error_template, $params['spbc_remote_call_action'], $unexpected_response);
+            }
 
-        // Considering empty response as error
-        if ($result === '') {
-            $error = sprintf($error_template, $params['spbc_remote_call_action'], 'EMPTY RESPONSE');
-        // Wrap and pass error
-        } elseif (! empty($result['error'])) {
-            $error = sprintf($error_template, $params['spbc_remote_call_action'], $result['error']);
-            // Expects 'OK' string as good response otherwise - error
-        } elseif (is_string($result) && ! preg_match('@^.*?OK$@', $result)) {
-            $unexpected_response = 'UNEXPECTED RESPONSE: "' . json_encode(substr($result, 0, 400)) . '"';
-            $error = sprintf($error_template, $params['spbc_remote_call_action'], $unexpected_response);
-        }
-
-        if (!empty($error)) {
-            $result = array('error' => $error);
+            if ($error === null) {
+                return $result;
+            }
         }
 
-        return $result;
+        return array('error' => $error);
     }
 
     /**