As of 31 January 2022, Microsoft will be implementing changes to enhance security of Microsoft 365 users. TLS (Transport Layer Protocol) 1.0 and 1.1 will no longer be supported and Microsoft will only offer support for TLS 1.2 from newer browsers and operating systems.
Windows 10/11 and other current operating systems and major browsers have TLS 1.2 enabled by default. However older operating systems may have issues when attempting to connect to Office 365 from certain devices/apps.
To ensure a smooth transition, we recommend you use updated and supported devices and apps that meet the current industry security standards. Microsoft has provided the following information on this change : https://docs.microsoft.com/en-us/troubleshoot/azure/active-directory/enable-support-tls-environment?tabs=azure-monitor#why-this-change-is-being-made