This is as of may 2019 as I used smart view last week just fine. I have several Samsung smart TVs ranging in age. I'm now unable to connect to any of them. I pull up screen mirroring on the TV then go to smart view on the note 8. It acts as if it's going to connect then black screens. Very frustrated with this hope Samsung has a solution. I've read through this community and tried many of the solutions to no avail.
Troubleshooting that I've done to present.
Restarted mobile device.
Made sure no background restrictions our pop up blockers were in place.
Made sure all TV and device were current on updates.
Made sure smart view was up to date and did a force stop and reopened.
Tried to download smart view app in app store didnt work ether uninstalled it.
Tried using wifi direct to stream using authorization code didnt work.
Made sure device and TVs all on same wifi network didnt work.
Think that's about it maybe leaving something out.
I had an issue with smart view connecting but only a black screen apeared on my tv. I reset my tv back to factory settings and went through the setup process and everything works fine. Just remember if your phone connects it isn't the phone, it's the tv.