Hi,
There are no known/current issues with Wealth-Lab Developer 6 authentication so it must be a local problem in your environment. According to
Microsoft support, the issue ("The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel") may be caused by the following reasons:
* You are using an invalid client certificate or an invalid server certificate.
* You are experiencing a TCP connection problem.
* The client computer is sending lots of data.
* A time-out setting on the server or on another network device is set too low.
* You are experiencing an HTTPS protocol compatibility problem.
Since our database indicates that you've been able to authenticate successfully before, first thing to try is to ask your IT person whether there are known network issues, or system security policy changes made recently etc.
Of other suggestions, you might like to try authenticating over a different WAN connection. It's the easiest way to tell if the issue has something to do with your network or with your computer.