Roku TVs won’t play after power outage

We had a brief power outage two days ago. Ever since, our 2 TCL Roku TVs and our Roku Express device (connected to our Sony TV) won’t work. They all have the same problem…

The TV turns on as normal. When we select a channel, it tries to load it, and it eventually says it won’t connect, check the internet connection, etc. 

On one TCL and on the Roku express, we checked the internet connection… it’s “excellent.”  We disconnected and reconnected our WiFi. Wireless connection is good. Internet connection is good.
We restarted (completely unplugged) our internet service/modems and reconnected.
We did system restarts. 
When we reconnect to the internet, it tries to install updates, but Error 003 appears. We’ve retried several times over several hours. Same message. And still the same problems. 

On the Roku Express, we did a factory restart (pushed the tiny hole with a straightened paperclip). It went through the setup and connected to the internet, good connection, good internet. But it won’t get past the internet setup screen, because when it tries to install an update, the error screen appears. The first error message after the factory reset said that it couldn’t install updates (it only stayed on a few seconds… didn’t get the error number). Afterward, every time we go through connecting to the internet, it again shows error 003 every time. And now we can’t even get back to the home screen since we’ve done the factory reset. 

I tried to connect the TVs to my phone’s hotspot, but we don’t get good cell service at my house, so it won’t work at all. All other devices connect to my internet/WiFi with no problem at all. 

I can play all my channels (including the Roku channel) on my phone (connected to the same internet the TV is connected to). With the Roku app, I tried to send a Roku show to the TVs from the app, and it says “Loading Channel,” but nothing ever happens. 

Any suggestions would be much appreciated.