As a result of the latest electronic messaging and privacy requirements around the world, SourceForge has implemented a number of changes that affect email privacy. One part of this is that it is no longer possible for project admins to view the member emails of their mailing lists.
The SourceForge mailinglist admin pages for your project will allow you to remove a specific email address and to change the moderated status of the subscribed emails. Some helpful links:
Thank you for your understanding and continued support,
The SourceForge team