Generally I find that restarting the router fixes this.
Sometimes I have to restart the Roku.
Very rarely, I have to unplug the Rokubfitprva minute or so then plug it back in
Roku Community Streaming Expert
I am not a Roku employee, only a user like you. Please, no support questions via private message -- post them publicly to the Community where others may benefit as well.
If this post solves your problem please help others find this answer by clicking " Accept as Solution.".
Streaming Stick 4K+ 3821 | Streaming Stick+ 3810 | TCL Roku TV 43S245/C107X