Intermittently losing internet connection
I have 3 ROKU units. One of them intermittently loses internet connect. The other 2 units still have internet connection, so it's not the router. I've been able to reconnect after going through the setup procedure but it usually takes 5 or 6 tries. It's losing connection more often lately. Is the unit burning out???
The Settings/System/About info was regarding your model number in this instance. (3930x). It also tells you if you are seeing an IP address and MAC addresses (which helps determine network function).
Since you have the 3930, and you are also using a cable ISP (AT&T), you will likely need to change the "Wireless Mode" (Wi-fi Mode) under your 2.4ghz Wireless Settings to b/g/n in your router.
The instructions for making this change are here for that particular router. (look at the "Access and verify gateway settings" section on the page). https://www.att.com/support/article/u-verse-high-speed-internet/KM1046181/
----
Some firmware updates to these cable ISP routers, coupled with the older hardware in the 2.4ghz-only devices like the Express 3930 are causing both connection/reconnection issues if the Wireless Mode is set to anything other than b/g/n (need all three of these speed protocols enabled in router settings).
You should be good to go after that.
Feel free to post back with an update or if you need more help.