Could not establish TLS connection on port 7001 - "unable to get local issuer certificate"

Question

tvcs: Event="Outbound TLS Negotiation Error" Service="SIP" Src-ip="10.0.7.168" Src-port="29127" Dst-ip="<Public IP>" Dst-port="7001" Detail="unable to get local issuer certificate" Protocol="TLS" Common-name="ewe.<domainname>.com" Level="1" UTCTime="2014-11-12 12:48:20,071" 2014-11-12T15:48:05+03:00
Getting above error on Expressway-C server while establishing TLS connection with Expressway-E in DMZ. I have enabled static NAT on Expressway-E and give the Public IP on peer address of Expressway-C. At that time, i was getting DNS resolution error  on Expressway-C so we added a host record on local DNS for Public IP. Later, I created CSR from both Expressway C & E server and ask local microsoft team to issue Local CA certificates. After uploading, i was getting above error (Failed to establish TLS). Also i have uploaded company (wilcard) Public certificates (issued from Geotrust) and we are getting the samer error and Expressway server could not establish TLS connection on port 7001. Firewall connections are done and i double checked it. 
Expressway ver 8.2

Answer 1

Yes, Exp-C > Peer Address (FQDN of Exp-E)
Certificate of Exp-E -> When generating CSR from Exp-E, automatically FQDN (Exp-E(hostname).domainname.com) will be shown. Then this CSR will be send to local CA or Public CA to generate a certificate. OR you meant to say in Exp-E CSR we need to add FQDN of Exp-C server also in alternative name and vice versa too.
Yes, root certificates & intermediate certificates are uploaded to trusted CA.