Question

I am trying to connect SMTP using the Oauth2 for Gmail , but getting the following issues.

Oauth token and email name are correct and works to connect IMAP.

I am following the example of google.

DEBUG SMTP: Authenticate with SASL
DEBUG SMTP: SASL mechanisms allowed: XOAUTH2
DEBUG SMTP: SASL AUTH command trace suppressed
DEBUG SMTP SASL: Mechanisms: XOAUTH2
DEBUG SMTP SASL: No SASL support
DEBUG SMTP: SASL authentication failed
DEBUG SMTP: Attempt to authenticate
DEBUG SMTP: check mechanisms: LOGIN PLAIN DIGEST-MD5 NTLM 
DEBUG SMTP: AUTH LOGIN command trace suppressed
DEBUG SMTP: AUTH LOGIN failed


javax.mail.AuthenticationFailedException: 535-5.7.1 Username and Password not accepted. Learn more at
535 5.7.1 http://support.google.com/mail/bin/answer.py?answer=14257 ol4sm17455809pbb.58

Answer 1

I just forget to call the initialize () method of OAuth2Authenticator class.

 public static void initialize() {
    Security.addProvider(new OAuth2Provider());
  }