Looking at the content of this message, this might be a warning that you shouldn’t ignore.
We are moving to TLS 1.2 for encryption
Plan For Change
Published On : 19 December 2017
Action required by 1 March 2018
To provide best-in-class encryption, and to ensure our service is more secure by default, we are moving all of our online services to Transport Layer Security (TLS) 1.2+. As a result, we will be removing support for TLS versions less than 1.2 from our online services, beginning March 1, 2018.
How does this affect me?
Starting on March 1, 2018, all client-server and browser-server combinations must use TLS 1.2 or later protocol versions to be able to connect without issues to Office 365 services. This may require certain client-server and browser-server combinations to be updated. Although current analysis of connections to Microsoft Online services shows that very few customers still use TLS 1.0 and 1.1, we are providing notice of this change so that you can update any affected clients or servers as necessary before support for TLS 1.0 and 1.1 is disabled. If you are using any on-premises infrastructure for hybrid scenarios or Active Directory Federation Services, make sure that these infrastructures can support both inbound and outbound connections that use TLS 1.2.
What do I need to do to prepare for this change?
We recommend you proactively address weak TLS usage by removing TLS 1.0/1.1 dependencies in your environments and disabling TLS 1.0/1.1 at the operating system level where possible. Begin planning your migration to TLS 1.2+, today. Please click Additional Information to learn more.
So if you are still using TLS 1.0 or TLS 1.1 then you might want to get these upgraded to TLS 1.2