Firebase 401 unauthorized error FCM

Question

I\'m trying to test out Firebase Cloud messaging APIs as all functionality is not available from console (notably customization of notifications when app is in background).

Answer 1

I too am facing the Same problem... I am using curl in php for posting and it works only if I have php files stored on my LocalHost server. When I try to use access the files via a free hosting online, then it say Unautorized 401.

So I would suggest if you can, use the Localhost.