Failure to to set up my book live to iMac

I have a 2T my book live and it worked fine with my pc running windows 7. It also works fine with my iPhone and iPad via the mobile app. I now have a new iMac but it cannot find my book when I try to connect via WD’s own wizard. It did when i originally connected to my pc. Sounds like the iMac but can’t see an obvious issue. Thanks for suggestions everybody.

Hi, what Mac OS X you have in the iMac?

Got the latest El Capitain thanks Tom