Not sure if your issue was resolved. If you are still facing this issue, please provide the output of the following openssl command
openssl s_client -host <yourRestServiceHost> -port <yourRestServiceSecurePort>
for google.com the above would be
openssl s_client -host www.google.com -port 443
(The above commands are valid for a Linux/Unix environment - for Windows you will need to install the windows version of openssl)