If you are filed as "unemployed" or "student", you will not have a "work verified email" box to type in. In addition, you will not be able to input a work verified email that is not a business email domain (i.e. personal email domains like yahoo, icloud, Gmail, Outlook etc).
To correct this go to your Participant Portal > Edit Profile > add your work verified email > Be sure to hit Save
In the meantime, you will still be able to apply for general population studies by going to "Browse Projects" and selecting projects that do not have a "💼" on the right-hand side of them (general population).