I'm having the same exact problem with my tv. Works fine using my hotspot, but will no longer work by connecting to a hotel/dorm connection, as well as the tab is different possible corrupted file dealing with direct-Roku connection when connecting to a dorm/hotel connection. I've even did a factory reset and still the same results. Please fix this issue soon Roku developers
I reached out to customer support and after some back-and-forth, the solution below seems to have worked for me. Thought I'd share in case it helps anyone else!
@kip21 OMG you legit saved my sanity! I don't know if this is a consistent fix yet, but it actually worked! I was trying all sorts of crazy stuff from screen mirroring to changing my MAC in a terminal (which was seriously complicated). I even started looking at/considering WiFi hotspots. I had updated and factory reset it semi-recently. That's around I noticed it stop working. I thought I had broke it somehow.