"EndNote is not responding. Error = -600"

I have recently upgraded Endnote X7 on Word for Mac 2016 and when I try to insert a citation (or use Endnote CWYW) I receive this error message:

“EndNote is not responding. Error = -600”

Any ideas on how to fix?

Many thanks

hb

See this knowledge base article to see if it helps. 

http://endnote.com/kb/139450