@moreganocarr are you using wix user or wix user backend. Because for the wix-user (frontend) there is the following restrictions
You can only send the email to the currently logged-in member. You can get that member’s ID using the id property of the currentUser .
But I’m not even sure if that restriction does not apply to wix-user-backend as well. You have to try (plz share your results) .
A workaround is to use a mail service provider to send your email via code