.mac account cannot received email
OS X 10.10.2 , Mail Version 8.2 (2070.6)
I got a family pack .mac long time ago. the main account use just find without any problem, but recently one of the family members account(which now each member account is individual now already) it has a @mac.com account still can login icloud and sent the email just fine, but this xxx@mac.com cannot received any email, I have test that xxx@me.comxxx@icloud.com can received email without anyproblem. Doest anyone know why this happened?
thanks for help
MacBook Air, OS X Yosemite (10.10.2)