3683980 - Emails fail with XS857, long text shows: 535 5.7.139 Authentication unsuccessful, SmtpClientAuthenticiation is disabled for the tenant.

• Emails are being sent from SAP system to Microsoft Office365 for transmission to the Recipient.
• These Emails are failing with XS857 - No delivery to  as logon data invalid.
• The long text of the error shows cause as  => 535 5.7.139 Authentication unsuccessful, SmtpClientAuthenticiation is disabled for the tenant. Visit
• Screen shot of the long text of the error message from SOST:
  
  
  
  "Image/data in this KBA is from SAP internal systems, sample data, or demo systems. Any resemblance to real data is purely coincidental."

• SAP Business Technology Platform
• SAP Basis release independent

XS857, No delivery to  as logon data invalid, 535 5.7.139 Authentication unsuccessful, SmtpClientAuthenticiation, , KBA , BC-SRV-COM , Communication Services: Mail, Fax, SMS, Telephony , Problem