Hi,chocolate sticks to almost everything, except on fat.
it seems (from far away) that your problem is not the chocolate itself, but theycaramel. If the caramel has a overly shine look, it could be that some fat is surfacing/splitting, making it difficult for the chocolate to stick.
for test purpose, check first the caramel, then do a test by coating something else (nuts?) to understand what you are doing incorrect.
Otherwise you can always "dust the caramel with something to roughen the surface.
cheers.