If you are experiencing issues with the one-time code, follow these steps and try again:
- Make sure your router's firmware is up to date
- Restart your router and reMarkable paper tablet
- Change the network security settings to WPA2, if you haven't already. Try the other available settings
- Make sure your network is not using a VPN service
- Change the Wi-Fi frequency from 5 GHz to 2.4 GHz or vice versa
- Change the Wi-Fi channel
If you are still experiencing the issue, connect your reMarkable to your phone's mobile hotspot and see if that helps.