The certificate module is designed to issue a certificate semi-automatically, so no one needs to create the certficate paper manually, check for prerequisites and send the paper to the participants.
You should define clearly, what "having passed the course" means. Based on that definition the locking conditions should be configured in the certificate.
Some thoughts on things that can happen:
- Students should be instructed that passing the course and receiving the certificate is a two-step operation. Students do not receive the certificate automatically after finishing the test, they have to open the certificate activity by themselves.
- Sometimes a certificate can be locked, allthough all conditions are met. In this case logging off and logging in again can do the trick.
- There are issues also discussed in this forum that certificates stay locked when teachers have changed the grade of a quiz manually. I think there is a fix for this.
- If the certificate shall be completely user-driven: you can always deactivate any locking options. Then everyone can obtain a certificate, as long as he is student in the course.
- If the certificate shall be completely teacher-driven: combine the certificate with an assignment activity. Students apply to the teacher that they want a certificate, and the teacher can grant it by giving the appropriate grade.