When new members sign up an email gets sent to filter.select@gmail.com
Unless you some kind of customization that sends out those emails, I can only think of one place should have a look at:


go to "Contributions" --> "Manage Contribution Pages"
next to the contribution page in question, use the link "configure" and then "Thank-You and receipting" 
tick the box "Email Receipt to Contributor" (if not ticked already) and check if "filter.select@gmail.com" is in the cc or bcc field.