@Renee59-
Might your router be one supplied by your internet provider? If so, your problem may have be caused by a recent update to your router. This has been reported lately with equipment from Xfinity and Cox, but there may be others.
Affected users report the router configuration needs to be switched from g/n security back to b/g/n. If you don't have access to your router's control panel you may have to have your internet provider do it for you.
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