Hello StorageMasters,
I work for NetApp doing clustered Data ONTAP consulting. Since you are likely using the thick OnCommand System Manager client, I'd try to reproduce the error using the onboard system manager - Point your browser to the cluster management LIF and see if you get the same message.
Afterwards, please take a look at this nice KB article - Top 10 FAQ on OnCommand System Manager: KB 3013893 and if none of the aforementioned apply (most commonly - TLS disabled on source browser) that you log a support case and provide the System Manager logs (how to at the bottom of the KB).
Enjoy!
Hadrian