Enable DNS-Sec For unbound

[Ramin Malekgahsemi]

Hi Dear Friend I want enable DNS sec Validation For Recursive mode Unbound

I use This link For 
https://plone.lucidsolutions.co.nz/linux/dns/enable-dnssec-for-unbound-resolver

Now When Type in CLI 
 unbound-anchor -a /etc/unbound/root.key 

Log to me 

[1581430016] libunbound[17599:0] error: failed to load trust anchor from /etc/unbound/root.key at line 5, skipping

How Can Download Latest Trusted Key For Unbound 

My OS is Centos 7 X64 and unbound  version is  
notice: Start of unbound 1.6.6.

Thx