diff --git a/src/Message.php b/src/Message.php
index 61c1a5dc..c1e15f82 100644
--- a/src/Message.php
+++ b/src/Message.php
@@ -77,7 +77,7 @@ public static function bodySummary(MessageInterface $message, int $truncateAt =
 
         // Matches any printable character, including unicode characters:
         // letters, marks, numbers, punctuation, spacing, and separators.
-        if (preg_match('/[^\pL\pM\pN\pP\pS\pZ\n\r\t]/u', $summary)) {
+        if (preg_match('/[^\pL\pM\pN\pP\pS\pZ\n\r\t]/u', $summary) !== 0) {
             return null;
         }