For those running Sophos in their enterprise for AV protection on their Mac platforms, please be aware that the Sophos application will prevent incoming calls to Jabber from ringing through. We have run into this issue with numerous users who have upgraded to Big Sur (myself included). A call placed to the user's directory number results in the call ringing through to all devices except the Jabber client on the Mac Big Sur. After a discussion with our Sophos support group, we have found that Sophos is having numerous issues with the network stack on Big Sur that is causing issues with a number of applications. One of those applications was the Cisco AnyConnect VPN client. There is no known workaround at this point in time. Removing (not disabling) Sophos does allow inbound calls to ring through. According to Sophos, they are working with Apple, but please be aware of this for your Jabber users on Mac before they upgrade to Big Sur if you are using Sophos.
