fb_message_api

curl

curl -X POST "https://graph.facebook.com/v2.7/me/subscribed_apps?access_token=PAGE_APP_TOKEN"

curl -X POST -H "Content-Type: application/json" -d '{
  "setting_type":"greeting",
  "greeting":{
    "text":"greeting message"
  }
}' "https://graph.facebook.com/v2.6/me/thread_settings?access_token=PAGE_APP_TOKEN" 

when ran in terminal, shows an error:

{"error":{"message":"Invalid OAuth access token.","type":"OAuthException","code":190,"fbtrace_id":"FbV8frn2vRj"}