Core issue
This issue can occur under these circumstances:
- The connection to the VPN concentrator is not configured properly.
- The interface address changed recently.
What is HTTPS?
HyperText Transfer Protocol with Secure Sockets Layer. HTTPS is a protocol which is used to transfer encrypted data over the Web.
Two primary differences between HTTPS and HTTP
- HTTPS connects on port 443, while HTTP is on port 80
- HTTPS encrypts the data sent and received with SSL, while HTTP sends it all as plain text
Resolution
To resolve the issue, perform this procedure:
- Make sure that the Cisco VPN 3000 Concentrator is configured properly, as documented in the Configure the Public Interface for Secure HTTPS Access section of Troubleshooting Connection Problems on the VPN 3000 Concentrator.
- Type https://admin to access the management interface, if WebVPN is also configured.
- If the address of the interface was changed, regenerate the Secure Socket Layer (SSL) certificates with the steps mentioned in article Cannot install SSL certificate on VPN 3000 series Concentrator for remote administration after upgrading software.
