Participants unable to join Zoom meeting

We organized a Zoom meeting today and ran into an issue as participants could not join. We had enabled Zoom registration prior to the meeting and manually approved of participants that were to join. However, when they clicked on the link for the Zoom meeting, they were taken to the registration form rather than the meeting itself. 

Could this issue be related to the manual approval of participants? Any good tips on how to avoid this from happening again in the future?