Note: The error code is the last 3 digits of the code you see in the error notification. For example, if you see the error notification Call failed (code: 2202404), the error code is 404.

If you are receiving Zoom Phone error 503: Service not available. Please try again later., this means that server issues might be preventing your call from getting through.

Try to call again later or contact your Zoom Phone admin for help. You may need to change your network firewall or proxy server settings.