Push Notifications error

hello to all or installed Push Notifications with google, or verified the site and everything ok, how active notification,
I get error “registration failed missing applicationserverkey and gcm_sender _id not found in manifest”, the log of home assistant does not give me errors.
grzie for your help

Did you find out the reason for this error?
I get the same after migrating my working installation from GCM to FCM.