diff --git a/src/pocketmine/utils/TextFormat.php b/src/pocketmine/utils/TextFormat.php
index 08cd5aa6f..6d106db1c 100644
--- a/src/pocketmine/utils/TextFormat.php
+++ b/src/pocketmine/utils/TextFormat.php
@@ -288,7 +288,11 @@ abstract class TextFormat{
 			}
 		}
 
-		return json_encode($newString, JSON_UNESCAPED_SLASHES);
+		$result = json_encode($newString, JSON_UNESCAPED_SLASHES);
+		if($result === false){
+			throw new \InvalidArgumentException("Failed to encode result JSON: " . json_last_error_msg());
+		}
+		return $result;
 	}
 
 	/**