My HTC VIVE Focus 3 is showing that it's online, but I keep getting network errors.

My device is showing as connected to Wi-Fi, but when I try to login into PeriopSim I get a network error

When logging into PeriopSim and you receive a network error, make sure your device is connected to the internet. You can check your online status by going to Settings > Connectivity > Wi-Fi. This will show if you're connected to your local network or not. You can also access Wi‍-Fi settings by pressing the VIVE button on the right controller, and then select More > Wi-Fi. 

If you're connected to your local network and you still can't log into PeriopSim or any other app or website, we recommend making sure your time and date are set correctly. If the date and time is off, the authentication server may not trust the certificate belonging to the headset and refuse to connect. You can verify if your date and time are set correctly by going to Settings > General > Date & Time