@meaton That seems to contradict the WWDC21 video "Accelerate networking with HTTP/3 and QUIC" where at 16:22 it shows this example... // Adjust stream properties let options = NWrotocolQUIC.Options () options direction = unidirectional let connection = NWConnection(from: group, using: options) Notice it's attempting to manually (?) extract a stream from the group (notice the "from: group" in the connection initializer).

I was experiencing the same issue on the Big Sur Beta. On a whim I ran a fix for a file sharing vulnerability that Apple released quite a while ago and lo and behold it worked. The following command fixed sharing for me: $ sudo /usr/libexec/configureLocalKDC Related security update: https://support.apple.com/en-us/HT208317