Maybe someone can tell me what I am doing wrong:

I created my own SSL certificate and installed it on my server. I wrote a really simple VB.NET program to access the SQL Server using encryption. The connection string works fine inside my building (on our network) but when I take the application outside of the building and try to connect it fails.
Outside of the building, I add

Address=xx.xxx.xxx.xxx,1433;

to the connection string.

The attempt gives me the error:
a connection was successfully established with the server, but then an error occurred during the pre-login handshake. (provider: SSL Provider, error: 0 - The certificate chain was issued by an untrusted authority

If I remove the encryption=True from the connection string, everything works outside the building but obviously without encryption.

I am doing this in a VB.NET windows application (not an internet app)

Thanks,
Ned