Previous to Big Sur Beta 4, I was able to connect to my NAS VPN Server via Network Preferences VPN profile. It had worked continuously for almost two years. However, after the Beta 4 upgrade(?), anytime I try to connect I get "The L2TP-VPN server did not respond." error. I have another mac that is running Catalina and using the same VPN profile and is able to connect. I have a third party app, Tunnelblick, on the imac that can't connect which is able to connect . I have restarted the mac, the server, reset the profiles to a no avail. Sure does appear to me that there is a bug in the network preferences in Big Sur. I have posted same issue in the Feedback Assistant on the Apple Developer website as well. Any suggestions from anyone. Thanks.