Account owners and admins can block users from signing in to Zoom from unmanaged Zoom Phone appliances which is enabled and allowed by default.

Notes:

• Allow users to sign-in to unmanaged Zoom Phone Appliances is set at the Device Management account level only, cannot be set for each device individually and cannot be locked.
• More on Zoom Device Management.

Prerequisites 

• Account owner or admin privileges
• Zoom Phone appliances

How to enable or disable sign-ins from appliances 

To disable Allow users to sign-in to unmanaged Zoom Phone Appliances:

1. Sign in to the Zoom web portal as an admin with the privilege to edit account settings.
2. In the navigation panel, click Device Management then Device List.
3. In the upper-right corner, click the Account Settings.
4. Enable or disable Allow users to sign-in to unmanaged Zoom Phone Appliances.
5. If the setting is enabled, click the toggle to disable it. If a verification dialog displays, click Disable to verify the change.