Password less SSH for non-interactive NUID

We have a script which rsyncs two directories on two servers. This rsync will happen with the ID svID. But the script runs with the Control-M ID opID. we have setup password less SSH for svID, but it fails with Host key verification failed when the script is executed by opID. As opID is a non-interactive ID, i could not setup the password less SSH. Please suggest.

Hi,
set public/private keys authentification.

Regards,