Important Notice: Please begin updating all your clients to Zoom 5.0 now. After May 30, 2020, all Zoom clients on older versions will receive a forced upgrade when trying to join meetings as GCM Encryption will be fully enabled across the Zoom platform. Click here for more information.
How to update:
Right click on the Zoom tray icon
Click on "Check for updates"
Allow Zoom to download the update
Once the download is complete, click on the Update button.
Wait for it to update, and restart itself.
If you are still experiencing issues, please refer to Zoom's article here.