I've been using Roku Express for a while and everything was fine until I did an update to the newest software about two weeks ago. Now, I couldn't access Roku at all as internet are so slow. I have both 2g and 5g wifi at home and it never has a problem with Roku before.
Already tried to do factory reset and other tips that I've found online but none have works.
If you have a cable ISP like Xfinity/Comcast, AT&T, or Cox, you will need to verify that your 2.4ghz band is configured to use b/g/n "wireless mode" as your Roku device is only 2.4ghz capable. It can not see or use the 5ghz band of your network.
After changing the wireless mode in your router to b/g/n, restart both your router and your Roku device and you should be able to connect again.
If the above is not applicable to you, post back your 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