Thank you for the inquiry!
For these issues, try clearing the cache and uninstalling the Roku mobile app from your phone. Then Restart the phone and Reinstall the Roku mobile app.
When the internet connection has been dropped or is not operating well:
Reboot the router (even if other devices have no problem finding and connecting). Sometimes that's all that's needed.
To clear Roku's memory, restart it. Depending on your Roku model and version number, the System restart option will be found under either Settings > System or Settings > System > Power.
Locate and connect to your network by going to Settings > Network > Set up connection. ( If that doesn't work, try disconnecting your Roku for a few seconds.) When it comes back up, see if you can set up the network connection.
We hope it helps!