AbortError: Registration failed - could not retrieve the public key

[leegiseong20030603]

FirebaseMessaging fcm = FirebaseMessaging.instance;
fcm.getToken().then((token){
print("FCM TOKEN : ${user.fcm_token}");
});

When I run that code, I get the error "AbortError: Registration failed - could not retrieve the public key". how can i solve it??

We proceeded with flutter web, and navigator.serviceWorker.registers were successfully applied normally.