Go to Setup -> Zoho Directory -> Security Policies.
Click on +Add Security policy (in right top corner) or you can edit Default Policy.
Go to Allowed IPs, then click on Add IP address.
Select the first option (make sure you are connected using GoodAccess.) and continue with Add.
Congratulations! From now your Zoho CRM page will be protected and accessible only by your team connected through the GoodAccess Client App.