Avamar: Avamar reports "Email Notification Failed" due to SMTP hostname lookup failure

admin@hostname:~/#: echo EmailHome Settings:; grep "smtp\|sender" /usr/local/avamar/var/mc/server_data/prefs/mcserver.xml
EmailHome Settings:
                <entry key="smtpHost" value="smtp-name.domain.com" />
                <entry key="admin_mail_sender_address" value="organization@domain.com" />
admin@hostname:~/#:

Telnet from the Avamar utility node to the SMTP server reports a lookup failure:

admin@hostname:~/#: telnet smtp-name.domain.com 25
telnet: smtp-name.domain.com: Name or service not known
smtp-name.domain.com: Host name lookup failure
admin@hostname:~/#:

admin@hostname:~/#: cat /etc/resolv.conf
domain Domain-Name.com
search Domain-Name.com
nameserver 10.x.x.57
nameserver 10.x.x.58
nameserver 10.x.x.46
admin@hostname:~/#:

Running nslookup resolves 7 IPs for the smtp host and 3 DNS servers:

admin@hostname:~/#: nslookup smtp-name.domain.com
;; Got SERVFAIL reply from 10.x.x.57, trying next server
;; Got SERVFAIL reply from 10.x.x.58, trying next server
Server:         10.x.x.46
Address:        10.x.x.46#53

Name:   smtp-name.domain.com
Address: 173.xxx.xx5.xx
Name:   smtp-name.domain.com
Address: 173.xxx.xx6.xx
Name:   smtp-name.domain.com
Address: 74.xxx.xx3.xx
Name:   smtp-name.domain.com
Address: 74.xxx.x8.xx
Name:   smtp-name.domain.com
Address: 74.xxx.xx0.xx
Name:   smtp-name.domain.com
Address: 74.xxx.xx3.xx
Name:   smtp-name.domain.com
Address: 74.xxx.xx0.xx

admin@hostname:~/#:

Notice how the only DNS server which is able to resolve the hostname of the smtp server is the last server entry in the resolve.conf file.

admin@hostname:~/#: cat /etc/resolv.conf
domain Domain-Name.com
search Domain-Name.com
nameserver 10.x.x.46
nameserver 10.x.x.57
nameserver 10.x.x.58
#nameserver 10.x.x.46
admin@hostname:~/#:

Test Telnet to smtp host:

admin@hostname:~/#: telnet smtp-name.domain.com 25
Trying 74.xxx.xx.28...
Connected to smtp-name.domain.com.
Escape character is '^]'.
220 smtp-name.domain.com ESMTP xxxxxxxxxxxxx.0 - gsmtp
helo hostname.Domain-Name.com
250 smtp-name.domain.com at your service
mail from: <organization@domain.com>
250 2.1.0 OK xxxxxxxxxxxxx.0 - gsmtp
rcpt to: <emailhome@avamar.com>
250 2.1.5 OK xxxxxxxxxxxxx.0 - gsmtp
QUIT
221 2.0.0 closing connection xxxxxxxxxxxxx.0 - gsmtp
Connection closed by foreign host.
admin@hostname:~/#:

Test emails from Avamar Administrator GUI > Edit Profile > Email Notification > Send Email. 
Check Avalanche page as well to see if it is updating.