Random failures with OAuth are often due to the time being somewhat off on the sending machine. Verify that the server's time is exactly correct, try syncing it with an Internet time server for best results going forward.
Another possibility is that some of the accounts have not accepted the Terms of Service. I believe SMTP, IMAP and POP connections will fail for an account until the user logs into the web interface and accepts the ToS / completes the Captcha. Jay -- You received this message because you are subscribed to the Google Groups "Google Apps Domain Information and Management APIs" group. To view this discussion on the web visit https://groups.google.com/d/msg/google-apps-mgmt-apis/-/GWa9iYRghO0J. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-apps-mgmt-apis?hl=en.
