I've had my Roku Express for 6 months without an issue, then out of nowhere, all my apps are having connection issues. When I go to check the connection, it says I have excellent connection. I've tried restarting the roku, forgetting and resigning in to my wifi and checking for updates with no success. The router is on the other side of the wall and I have a Roku TV elsewhere in my house that works absolutely fine. This issue is happening across all apps so I would think this would be an issue with Roku and not the apps, especially since the same apps work fine on my Roku TV.
While it is certainly possible that something has failed in your Roku unit, odds are it's just an internet connection problem. It's quite possible for one Roku to need to reconnect to your network while others have no problems.
Here's what has worked for me.
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.
I am having an issue in which I get the message that there is a network connection issue. However, the voice continues, but not the video. I have tried all of the steps you suggest. I have restarted router, Roku, and streaming app. Any other suggestions?