@Bford2
If you have a cable ISP (Xfinity/Comcast, Cox, or AT&T), you will need to verify that your Wireless Mode (protocol) is set to b/g/n in your router. (login to your router via admin or app).
You are correct that the standard Roku Express models (non 4k/4k+), are single band 2.4ghz-only devices. They cannot see or operate on the 5ghz band.
Instructions for Changing the Wireless Mode Settings….
Xfinity / Comcast → ( https://www.xfinity.com/support/articles/change-wifi-mode-admin-tool-xfinity-xfi ) with a walkthrough ( https://community.roku.com/t5/Network-Wireless-Wired-Connections/Error-014-30-stuck-for-three-days/m...)
Cox → (https://www.cox.com/residential/support/managing-your-in-home-network-with-my-wifi.html)
AT&T → (https://www.att.com/support/article/u-verse-high-speed-internet/KM1046172). You can select your appropriate router from the drop down menu.
Restart both your Router and Roku devices after making the above change.
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Feel free to post an update if you need more help or the above is not applicable. Include router model number and ISP (internet service provider).
Roku Community Streaming Expert
Just another Roku user... I am not a Roku employee.
Insignia RokuTV, Ultra 4660, Premiere+ 3921, Express 4k+ 3941, Streambar 9102
