You can try the steps on our website:
https://support.clarivate.com/Endnote/s/article/EndNote-X8-Mac-and-EndNote-online-Mac-CWYW-tools-in-Microsoft-Word-2016-Troubleshooting-guide?language=en_US
You can also contact Technical Support for help.
1-800-336-4474 option 4 then 1
or
https://endnote.com/contact/