[Solution] Google 550 Authentication required
Was having issue with Google Apps email recently. The email kept on bounce back with the following error. Delivery to the following recipient failed permanently: email@example.sg Technical details of permanent failure: Google tried to deliver your message, but it was rejected by the recipient domain. We recommend contacting the other email provider for further information about the cause of this error. The error that the other server returned was: 550 550 authentication required (state 14). Step 1 : (Basic) Check your MX record. This is probably the basic step that most people already did. Skip if you have already setup. Check your MX records - http://www.mxtoolbox.com/ Setup Google Mail records - http://www.google.com/support/a/bin/answer.py?answer=140034 Step 2 : Google SPF TXT record For me, this help solves my problem. Although I'm not entirely sure why some of my other Google Apps email works without this TXT record. Check your TXT records - h...