Hi,
To test your subscription center, you must send yourself a subscription-center link in a live email from a live customer journey. The subscription center won't work correctly if you open its URL directly, or select a link sent in a test message.
Subscription centers only work when they "know" who they are talking to. This enables the subscription center to display existing contact information in editable fields (like name and email), and also to indicate which of the available subscription lists the viewer already belongs to. The only way most people will be able to open the subscription center is by selecting a link sent to them in a marketing email from a customer journey. Links such as these include an ID that lets the subscription center know which contact has requested the page. (In fact, all links in marketing emails include an ID that's linked to both the contact and the message, which enables the system to report which link each contact has selected in each message.)
If you open a subscription center by opening its URL directly (or by using a link sent in a test message), an error message will display indicating that the system is not able to verify your contact information.
