On a macOS Big Sur computer installed with Symantec Encryption Desktop and Symantec Endpoint Protection, the messaging function of Symantec Encryption Desktop may not work.
Symantec Development is aware of this issue and is currently working to resolve. Please refer back to this article for updates, or contact support for more information.
The following are useful articles when working with macOS Big Sur and Symantec Encryption Desktop 10.5 MP1:
207386 - Deploying Symantec Encryption Desktop with MDM deployment settings on macOS Catalina
207391 - (Fixed in Big Sur 11.2) Configuring SSL/TLS for email communication for the Mail app with macOS Big Sur/macOS 11 and Symantec Encryption Desktop 10.5 MP1
207397 - How to allow system extensions and configure MDM profile on macOS Big Sur 11.x with Symantec Encryption Desktop 10.5 MP1