Resolution
If a list admin is deleted from ListManager's list of admins for a list, that user will no longer be able to view the list.
If all admins are deleted, only a site or server administrator can view the list.
The list is still there, but the user logged in must be an administrator of the list before that user can view the list.
Make the current user an admin for the list by logging out and logging in as a site or server admin, then using that admin account to upgrade the member to list admin. Or create a new admin.
If the problem happens with a Shared Hosted account where all admins for a list have been deleted, please contact the Support Team so they can create a list admin for the list.
