Connection not secure
 

When I try to connect with vbulletin I get this warning

Quote:
This Connection is Untrusted





You have asked Firefox to connect
securely to www.vbulletin.com, but we can't confirm that your connection is secure.

This Connection is Untrusted





You have asked Firefox to connect
securely to www.vbulletin.org, but we can't confirm that your connection is secure.

Can someone explain what is going on? How can I safely purchase VB if the site can't be confirmed as secure?