The same issue for me, I'm trying to debug the net core application on mac and see error:
(lldb) process attach -p 3304
error: attach failed: attach failed (Not allowed to attach to process. Look in the console messages (Console.app), near the debugserver entries when the attached failed. The subsystem that denied the attach permission will likely have logged an informative message about why it was denied.)
Running lldb with sudo not helping to me.