If you restrict any access to your PSA tool or Office 365 environments to specified IP’s or a geolocation, you will need to whitelist the following IP addresses.
This list of IP’s is a complete list that our scale out platform may use as it scales out and back down to process your license sync.
For Geolocation these should show as Azure North Europe
Where possible, we will send all outbound connections via these IP addresses. In most cases this should be all you will need to whitelist to your PSA service if required.