Have the same problem.with mine..
Everything was working fine..until Samsung update require...so I did....the phone been **bleep** ever since..
Samsung went backwards...in my theory...
My Note 8 doesnt screen cast anymore either since the Oreo update. It connects and casts for literally 2 seconds and then drops the connection and says "Smart View has stopped working."
I've tried everything in this thread, no luck.
I believe it is definitely a bug in an Android update.
I had a Note 8 which connected fine to my TV with a Microsoft Miracast dongle until a system update after which it would not connect at all. I broke that phone and got another Note 8 and the exact same thing occurred, it connected fine until a system update and now will not connect at all.
I had same problem just fixed it! Hope it works for you. Press on the smart view , but hold on to it , it takes you to a screen that tells you, about smart view, press on that, once you get there you will have a choice to [force stop], press on that. You can now exit and try your smart view now. That should do it.