Core issue
The PIX is not enabled for the level of encryption the PC is requiring.
For example, this message is displayed if the PIX can only do 40-bit encryption and the PC requires 128-bit encryption.
Resolution
- Issue a show version command and verify that the appropriate level of encryption (DES or 3DES) is enabled on the PIX.
- Check the encryption level and requirement settings on the PC and the PIX.
- Try the connection using a different PC.