Yes, d428.org can receive emails.
Yes, d428.org seems to be a legitimate domain.
A record
184.168.131.241
MX records
ALT1.ASPMX.L.GOOGLE.COM
64.233.186.26
ALT2.ASPMX.L.GOOGLE.COM
172.253.116.26
ASPMX.L.GOOGLE.COM
172.217.197.26
ASPMX2.GOOGLEMAIL.COM
64.233.186.27
ASPMX3.GOOGLEMAIL.COM
172.253.116.27