Below the username/password fields is a line headed with "Server:" After the colon it should read "k12connect.ca", w/o the quotation marks. Is that in place?
If not, click on the arrow next to "Advanced" below the "Server" line.
More buttons will become visible.
Click on "Setup"
In the new window, fill "k12connect.ca" in the line headed with "Server:"
Click on "Save"
You should now be able to connect to FirstClass with your credentials.