Hello & Welcome to JustAnswer.
Thank you for your question. I will do my best to assist you. My name is Jamie.
I would first do a soft reset on your Roku3
From your remote follow these steps.
If that doesn't work I would then do the hard reset. A hard reset will clear all settings from the device and reset it to factory defaults.
If a soft reset doesn’t fix your problem, a hard reset may be your only option. This will clear all data off the Roku and reset it to factory default settings.
From the Home screen, select the following depending on your device:
Does your roku3 show what ip address it obtained from your router?
Above Wireless MAC you should see the ip address. If you don't have one there that means your Roku is not grabbing an ip from your router. You mentioned having an ethernet connection as well. With the ethernet plugged up directly to your internet router, do you see an ip address then ???
Glad you got it fixed.