I get this 020 every time I turn the system on. My Roku is a few months old. It worked fine. Now, in the last few days, I get this error code and can't watch a thing until I unplug every plug and plug them back in. I'm paying for various streaming services that I cannot watch because of this Roku device! I'm running out of patience and going back to cable if this cannot get resolved.
Specifically what Roku device do you have? If it's that new, it might be defective, and Roku is very good about warranty support.
Usually with an error like this we suspect a setting in your wireless connection. If you have a cable company as your ISP, they are known for making changes to the modem without advising the customer. But since you can restore a connection with a reboot, I'm less likely to consider that. But it might not hurt to check the Mode setting on your 2.4 GHz radio and ensure it's set to B/G/N. If your ISP has you locked out from making that change, you'll have to contact their tech support for assistance.