zoom registration page with get-parameter

[rxx]

I want to track, who invited someone to a webinar.

I created a custom question for the webinar registration.

invitedby

Referrer

When i open this url, the forms will not be prefilled. Why?
https://us02web.zoom.us/webinar/register/WN_zJD8ilB5Q0i2TT0Db1QKew?Referrer=fqwfqw&invitedby=test