diff --git a/samples/mpa/src/main/java/com/webauthn4j/springframework/security/webauthn/sample/app/web/WebAuthnSampleController.java b/samples/mpa/src/main/java/com/webauthn4j/springframework/security/webauthn/sample/app/web/WebAuthnSampleController.java
index 44bd3746c..7ed680844 100644
--- a/samples/mpa/src/main/java/com/webauthn4j/springframework/security/webauthn/sample/app/web/WebAuthnSampleController.java
+++ b/samples/mpa/src/main/java/com/webauthn4j/springframework/security/webauthn/sample/app/web/WebAuthnSampleController.java
@@ -154,7 +154,7 @@ public String create(HttpServletRequest request, @Valid @ModelAttribute("userFor
 
 			WebAuthnAuthenticator authenticator = new WebAuthnAuthenticatorImpl(
 					"authenticator",
-					user,
+					user.getUsername(),
 					registrationRequestValidationResponse.getAttestationObject().getAuthenticatorData().getAttestedCredentialData(),
 					registrationRequestValidationResponse.getAttestationObject().getAttestationStatement(),
 					registrationRequestValidationResponse.getAttestationObject().getAuthenticatorData().getSignCount(),