Error 100000403 indicates that the user is experiencing connectivity issues caused by a network firewall or antivirus software preventing connection.

How to fix it

To fix this issue, check your network firewall or proxy settings. If you are experiencing this issue while using Zoom Rooms, check your firewall configuration.

If the issue persists, submit a request to Zoom Support for troubleshooting assistance. Please provide the following:

• What operating system you are using
• What you were doing when you received this error
• Meeting ID, if in a meeting or trying to join/start a meeting