Could be you just need to rehestablish your network connection.
This has always worked for me to re-establish my net connection when it has been lost or not performing well:
Restart the router (even if other devices have no problem finding and connecting). Sometimes that's all it takes, if not keep going.
Restart the Roku to clear its memory. Depending on your Roku model and Roku version number you'll find the System restart option under either Settings > System or Settings > System > Power. Again sometimes that's all it takes, if not keep going.
Find and connect to your network via Settings> Network > Set up connection
If that doesn't fix it, try disconnecting the power to your Roku for a few seconds. When it comes back up, see if you then can set up the network connection.
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
I am also experiencing this issue. When I click on Prime Video, the screen just goes black. No error received. No sound. I have model 3910RW. I updated my software and Prime video. We have completed a system restart, unplugged the Roku and router and started over.
I cannot open Amazon Prime. This happened last week with Amazon Music but it seems to work today.