Question:
Is it possible for RMS to use the Office365 SMTP server?
Answer:
RMS will not be able to connect to Office365 using SMTP, as RMS does not yet support TLSv1.2 for this connection. This is required by Office 365. You will likely see the following message when you attempt this:
Authentication failed; nested exception is javax.mail.AuthenticationFailedException: 421 4.7.66 TLS 1.0 and 1.1 are not supported. Please upgrade/update your client to support TLS 1.2. Visit https://aka.ms/smtp_auth_tls. [DX1P273CA0010.AREP273.PROD.OUTLOOK.COM]
Microsoft has created an opt in endpoint that legacy clients can use with TLS1.0 and TLS1.1. To use TLS1.0 and TLS1.1, follow the below steps:
- Set the AllowLegacyTLSClients parameter on the Set-TransportConfig cmdlet to True
- Legacy clients and devices will need to be configured to submit using the new endpoint smtp-legacy.office365.com (see image below for RMS email configuration example)
Note: The US Government cloud instance uses TLS v1.2 only, it will not accept the older TLS versions.
More information can be found about the Exchange Online endpoint for legacy TLS clients from the following link:
https://docs.microsoft.com/en-us/exchange/clients-and-mobile-in-exchange-online/opt-in-exchange-online-endpoint-for-legacy-tls-using-smtp-auth
