If you are having trouble getting into the conference, please make sure your Zoom client is updated.
From Zoom Website
https://support.zoom.us/hc/en-us:
Important Notice: Please begin updating all your Zoom applications to version 5.0 or higher. After May 30, 2020, all Zoom applications on older versions will receive a forced upgrade when trying to join meetings as GCM Encryption will be fully enabled across the Zoom platform. Learn more on how to update your Zoom application or update now.