553 sorry, that domain isn't in my list of allowed rcpthosts
Este error se resuelve con :
Editar :
nano /var/qmail/control/rcpthosts
Editar :
nano /var/qmail/control/virtualdomains
y reiniciar qmail :
service qmail reload
sh /script/upcp
sh /script/fixmail
sh /script/fixwebmail
sh /script/fixhorde
service xinetd restart