There are two scenarios here:
- Your device is identifying that you're behind a captive portal but you don't seem to be able to reach the login/registration page.
- You know you are behind a captive portal but the device is unable to identify it.
Here are some things that could help you (not guaranteed):
- Sometimes creating a new "Clear Network" and connecting to it (can be done in the Administration Interface on the "Networks" page) will allow you to reach the captive portal page and login. Once logged in, you can then switch back to a VPN or Tor network and work securely.
- Sometimes, you will need to open a browser and go to a specific URL to reach the captive portal page (eg. http://www.google.com).
- Maybe, we have already fixed some of the issues that you are experiencing but your device has not updated yet, you may want to upgrade manually to the latest firmware