diff --git a/src/Options/Authentication.php b/src/Options/Authentication.php
index ba18429a..36413ca7 100644
--- a/src/Options/Authentication.php
+++ b/src/Options/Authentication.php
@@ -82,7 +82,7 @@ final class Authentication extends AbstractOptions
     /**
      * Callable function to check if a credential is valid
      */
-    protected mixed $credentialCallable;
+    protected mixed $credentialCallable = null;
 
     /**
      * If an objectManager is not supplied, this metadata will be used