The GLAM-US mailing list has some activity, but there are no list owners specified on https://lists.wikimedia.org/mailman/listinfo/glam-us. At least one, and preferably two or three, people should be assigned as owners for the list.
@Pine reached out to the admins via email, and Sarah replied back she was happy to continue to maintain it, but simply had lost the admin password.
I've processed a password reset, which sent out the new password to the registered list owner admin addresses.
I think that should resolve this, please re-open if not!