that's pretty much the default error when snapvault does not work
if you can ping the source filer from the destination, then it is probably a permission or config issue.
as Eugene already said, check snapvault.access. for testing, set options snapvault.access * on both source and target.
and besides snapvault.enable, also check if options licensed_feature.nearstore_option.enable is on.
if that does not work, we need more info:
Ontap version
what's your exact commandline
snapvault status