[CentOS-es] problemas con los correos

[VICTOR MANUEL VARGAS GONZALEZ]

buenas tardes

me pueden apoyar en decirme por que cuando mando un email a unas direcciones m esta marcado error .Este es el error


The original message was received at Wed, 5 Oct 2016 14:28:21 -0500 from [192.168.0.253]

----- The following addresses had permanent fatal errors ----- <administracion en cyanmedica.com<mailto:administracion en cyanmedica.com>>

    (reason: 554 bosimpinc12 bizsmtp  Connection rejected. Reverse DNS for 189.240.35.147 does not exist.) <cesar.athie en cyanmedica.com<mailto:cesar.athie en cyanmedica.com>>

    (reason: 554 bosimpinc12 bizsmtp  Connection rejected. Reverse DNS for 189.240.35.147 does not exist.) <servicio.clientes en cyanmedica.com<mailto:servicio.clientes en cyanmedica.com>>

    (reason: 554 bosimpinc12 bizsmtp  Connection rejected. Reverse DNS for 189.240.35.147 does not exist.)

   ----- Transcript of session follows ----- ... while talking to mx.mydomain.com.:

<<< 554 bosimpinc12 bizsmtp  Connection rejected. Reverse DNS for 189.240.35.147 does not exist.

554 5.0.0 Service unavailable


tengo centos 6.4 y uso sendmail


gracias