Account Engagement Email field in the 'Email Preference Center' or 'Unsubscribe' page contains asterisks and is not editable

So long as the link is being populated through the standard {{EmailPreferenceCenter}} (HML) or %%email_preference_center%% (PML) tag (or a custom one, as outlined in the following documentation Add a Custom Email Preference Center to an Email) the page will work as intended.

When that tag is used in an email, it will be re-written upon sending, using a unique hash determined by the recipient. When the link is clicked, we'll display the first letter of the recipient's email and of their domain, but obscure the rest with asterisks such as c******2@f*****e.com. This field is read only.

If a cookied prospect reaches the Email Preference Center page through a means other than the {{EmailPreferenceCenter}} (HML) or %%email_preference_center%% (PML) tag, the field populates with the email address of the corresponding prospect. Again, this cannot be edited and the email address shown will be masked.

If a prospect reaches the Email Preference Center page through a means other than that tag in an email, and they are *NOT* cookied as a prospect, the field will be blank (nothing will be masked) and cannot be filled in.

You can test this by following these instructions:
1. Completely clear your browser cookies and cache >> browse to one of your Email Preference Center pages via the link in Account Engagement >> the field should be empty.
2. Fill out an Account Engagement form, using fake information and a fake email address >> browse to the Email Preference Center page >> the field will have that fake email address.
3. Send an email (cannot be a test email) to your actual email address through Account Engagement >> click on the Email Preference Center link >> the field should prefill with your actual email address.