I work for a small television station and we have a ROKU channel that is having issues (Blue Mountain TV). Last Friday when I checked on the channel it was working fine. Yesterday we noticed that the channel would fail to load and return to the home screen. There is a brief error message that pops up that reads, "Network Error: There is a problem connecting to the network. Please go to Settings to check your network settings." The network settings are fine. All other apps launch and play perfectly fine. My developer has checked our channel and it is reporting no issues on the back end. I have an Express 4K+ on loan and the channel loads and works fine on that device. But my express is having issues. There are a few other people reporting the same issue. Not sure what devices they are using. I've tried every fix I could find in the forum with no luck. I uninstalled the app, restarted the device and reinstalled the app with no luck. I even took the batteries out of the remote and used the remote app on my phone. None of these things have resolved the issue. Below is the data of the device that is not able to connect. I can include data for the device that can connect if that would be helpful.
Installed and tested this channel for you on Ultra 4660, Express 4k+ 3941, and an Insignia RokuTV and all received a slight loading circle, the quick flashing network error message and then crash back to Home Screen so issue is not with your Roku Express device.
Your developer may need to head over to Roku's Developer forum for some help on this one if not seeing issue.