The connection has been verified, and the external IP address you received is shown below the circle.
The extension is establishing the connection and verifying it. This normally takes a couple of seconds.
Either the connection failed and the reason is shown, or the IP leak protection has triggered and browser internet access is temporarily blocked.
This is the IP leak protection working as intended: the link to the node was lost, so the extension cut off access to keep your real address from going out. Wait for the node to come back and the tunnel will restore itself. If you need to get online right now, press “Unblock internet” — the browser continues without the tunnel.
Only one extension can control the browser's proxy settings. If you have Proxy SwitchyOmega, ZeroOmega or anything similar installed, disable it — otherwise the browser will report that the settings are controlled by another extension.
Nebula Network access is issued and maintained by your organization's administrator. If the connection will not come up and none of the reasons above apply, contact them — they can see the state of your token and of the exit node from their side.