Signup and purchase not recorded

I am testing the "Affiliate Advanced Settings" with Membership plugin and for some reason it does not work correctly.

If I use the normal link such as: http://www.adddiagnosis.net/adhd-test-online/?ref=solodi-98 everything seems to be in order. However, if I add the domain in the "Affiliate Advanced Settings", and use the link without the "ref" parameter, such as, http://www.adddiagnosis.net/adhd-test-online/ and then click on the link from the web site of the domain in the "Affiliate Advanced Settings", the click is registers, but the signup and purchase does not.

Any suggestions?