diff --git a/backend/mpc-system/test_signing.go b/backend/mpc-system/test_signing.go
index 80a15990..08c37a71 100644
--- a/backend/mpc-system/test_signing.go
+++ b/backend/mpc-system/test_signing.go
@@ -68,7 +68,7 @@ func main() {
 	// Create signing session via account-service
 	// This account has threshold_t=1, so should only need 2 parties (t+1=2)
 	signingData := map[string]interface{}{
-		"username":     "wallet-fb51d689",
+		"username":     "wallet-29f558a5",
 		"message_hash": messageHashHex,
 	}