Subit button are grayed in some candidates job applications:

Summary

Candidates who receive an invitation to apply or candidates who have already applied for another job requisition, cant end process and submit job application.

Content

Subit button are grayed in some candidates job appliations:
Scenario 1: candidate search a job in career site; fill all fields, then apply without problems.
Scenario 2: prospect receive an email inviting to apply. He did click in link of the email, go to the career site, fill all field, but, apply button (submit) are grayed; then candidates cannot ends their job application.
Any idea about what is happen?