On MacOS/latest, Safari/latest (plus going back in time 4 years). This problem has always plagued me, yet does not seem to be a mentioned problem. Basically, I have many instances of Neo4j 3.4.x and 3.5, local and cloud, and the issue happens with all of them.
When I try to Sign In for Browser Sync, it will launch a separate Auth window, but then that window auto-closes before I can interact with it. Every once in a while, I can actually complete the process and sign in, but it's rare. I believe I've struggled a little in Chrome as well, but not to the same degree.
Does anyone else ever see this? Seems like it's just me (but like I say, it's been going on for years).