Experiment no longer shows 'participant' text entry option once linked through SONA

Hi all,

I am having an issue linking my experiment to SONA. I have a dialog box on the experiment startup that is ‘participant’. I have followed the instructions here but when I type in the following the ‘participant’ disappears:


However, when I type in the pilot link and append it with the ?participant=%SURVEY_CODE%, everything shows up correctly!

Am I severely misunderstanding how the URL parameters work?

Any help would be appreciated!

Thank you!