How To Solve "token Retrieval Failed: Authentication_failed"?

I have implemented all documentation but still getting this error. This is my log: W/FirebaseMessagingPlugin(29848): getToken, error fetching instanceID: W/FirebaseMessagingPlugin

Solution 1:

I have fixed this issue by changing the IPV4 DNS of my network adapter from automatic to 8.8.8.8 (Google's Public DNS)