mod_quiz_start_attempt to set a user override for opening a quiz

Hi

I'm trying to use a webservice command to set a user override for when a quiz opens for a specific user

Does anyone know how I would do this? I'm trying below command but it gives me an error.

{"exception":"invalid_parameter_exception","errorcode":"invalidparameter","message":"Invalid parameter value detected"}

https://xxxmysite.com/webservice/rest/server.php?wstoken=xxxxxxxx&wsfunction=mod_quiz_start_attempt&moodlewsrestformat=json&quizid=44414&userid=25285&quizopen=1704067200&forcenewattempt=1