We changed our email convention and our team needs to associate a new email address with their existing box accounts.  When I try to add this under Account Settings, I get this error: 

You cannot use an email address from an unverified domain as your secondary email address. Ask your admin to validate the domain you want to use or contact your Box support representative.

I am also a Box Admin and I can't figure out how to verify our email domain.  Can you please send me instructions how to do this?  Or log into our back-end and just verify this domain, which is the same domain as everyone on our team's existing Box accounts?  Thank you!