Hi there! Celine from Figma here, happy to assist!
This is usually happens if you are trying to access Figma through a VPN (Virtual Private Network) or proxy service (which is not possible).
If you’re using a VPN or proxy, please ask your IT team or system administrator to unblock Port 443. This is the standard port for websites that are run over SSL (Secure Sockets Layer). As a quick workaround, please also try switching to a different internet connection to see if the issue persists.
If you're still running into the issue, our support team can take a closer look. I’ve just sent you a DM with the next steps for further investigation. Please take a look when you can!