diff --git a/composer.json b/composer.json
index 0d33cdf..e04b32e 100644
--- a/composer.json
+++ b/composer.json
@@ -13,8 +13,7 @@
     "require": {
         "php": ">=5.3",
         "react/promise": "^3.3 || ^2.1 || ^1.2.1",
-        "react/socket": "^1.17",
-        "ringcentral/psr7": "^1.2"
+        "react/socket": "^1.17"
     },
     "require-dev": {
         "phpunit/phpunit": "^9.6 || ^8.5 || ^5.7 || ^4.8.36",
diff --git a/src/ProxyConnector.php b/src/ProxyConnector.php
index 2e3575b..c9347fe 100644
--- a/src/ProxyConnector.php
+++ b/src/ProxyConnector.php
@@ -5,7 +5,6 @@
 use Exception;
 use InvalidArgumentException;
 use RuntimeException;
-use RingCentral\Psr7;
 use React\Promise;
 use React\Promise\Deferred;
 use React\Socket\ConnectionInterface;
@@ -183,30 +182,30 @@ public function connect($uri)
                     $fn = null;
 
                     // try to parse headers as response message
-                    try {
-                        $response = Psr7\parse_response(substr($buffer, 0, $pos));
-                    } catch (Exception $e) {
+                    if (!preg_match('/^HTTP\/1\.[01] ([0-9]{3})( .*)?\r\n/', $buffer, $matches)) {
                         $deferred->reject(new RuntimeException(
                             'Connection to ' . $uri . ' failed because proxy returned invalid response (EBADMSG)',
-                            defined('SOCKET_EBADMSG') ? SOCKET_EBADMSG: 71,
-                            $e
+                            defined('SOCKET_EBADMSG') ? SOCKET_EBADMSG : 71
                         ));
                         $stream->close();
                         return;
                     }
 
-                    if ($response->getStatusCode() === 407) {
+                    $statusCode = (int) $matches[1];
+                    $reasonPhrase = isset($matches[2]) ? trim($matches[2]) : '';
+
+                    if ($statusCode === 407) {
                         // map status code 407 (Proxy Authentication Required) to EACCES
                         $deferred->reject(new RuntimeException(
-                            'Connection to ' . $uri . ' failed because proxy denied access with HTTP error code ' . $response->getStatusCode() . ' (' . $response->getReasonPhrase() . ') (EACCES)',
+                            'Connection to ' . $uri . ' failed because proxy denied access with HTTP error code ' . $statusCode . ' (' . $reasonPhrase . ') (EACCES)',
                             defined('SOCKET_EACCES') ? SOCKET_EACCES : 13
                         ));
                         $stream->close();
                         return;
-                    } elseif ($response->getStatusCode() < 200 || $response->getStatusCode() >= 300) {
+                    } elseif ($statusCode < 200 || $statusCode >= 300) {
                         // map non-2xx status code to ECONNREFUSED
                         $deferred->reject(new RuntimeException(
-                            'Connection to ' . $uri . ' failed because proxy refused connection with HTTP error code ' . $response->getStatusCode() . ' (' . $response->getReasonPhrase() . ') (ECONNREFUSED)',
+                            'Connection to ' . $uri . ' failed because proxy refused connection with HTTP error code ' . $statusCode . ' (' . $reasonPhrase . ') (ECONNREFUSED)',
                             defined('SOCKET_ECONNREFUSED') ? SOCKET_ECONNREFUSED : 111
                         ));
                         $stream->close();