I assume that you replaced your old router with a new one supplied by your ISP, both routers had built-in Wi-Fi and you have no other access points. If not, please provide details.
Log into the new router and set the SSID(s) and Wi-Fi password(s) the same as on the old router.
Please be more specific. If you are unable to set the SSID and password on the new router, post make and model and perhaps we can help. If you don’t remember the old router settings, if you still have it, plug it in, connect a computer, and log in. Even though it won’t have internet access, you should be able to view the settings. Otherwise, look at the settings of a device that was previously connected to it. In some cases, you need a ‘trick’ to view the Wi-Fi password.
Once the old SSID and password has been restored, if the Rachio has not come back online, try power cycling it. If no luck, please report Rachio model, state of the lights, and whether other devices can connect to the new router without reconfiguration.
If the above all fails, you will need to provision Rachio for a new SSID and password. It’s easiest to do that with a phone or tablet that can run the Rachio app.
Does your kid, parent, etc. have a suitable phone you can borrow? If not, how about a neighbor or friend? If because of Covid, you aren’t taking any visitors, consider upgrading your phone. A phone so old that it can’t run the app is probably 2G and 3G only. If you are in a developed country, it’s likely that 3G will be soon shut down and you will have to upgrade anyway.
If your Rachio is gen 1 or 2, you will need to somehow obtain or borrow a device that can run the app. For Gen 3, you can use a Windows, Mac or Linux PC to set up new Wi-Fi. See
If you still have trouble, post details of what goes wrong (error messages, light codes, etc.)