If you have one property:
Log in to the extranet.
Navigate to Property > Messaging settings > Security settings.
Complete two-factor authentication if prompted.
Click on Add a Link and input the URL to whitelist.
For additional URLs, click on +.
Click Add domain to finalize.
If you have multiple properties:
Log in to your group account in the extranet.
Select a property from the home page menu.
Navigate to Property > Messaging settings > Security settings.
Complete two-factor authentication if required.
Click on Add a Link to input the URL for whitelisting.
Use + for additional URLs.
Click on Add domain to save.
To apply the settings across all properties, click Apply to all properties and confirm in the pop-up window.
The changes will now be applied to all properties.

