Any resyncing should only be done by contacting tech support directly. The process seemed to have changed over time, with various updates, and following any older steps do not always seem to work. So I would go to support rather than ask here.
1-800-336-4474 option 4 then 1 or
https://support.clarivate.com/Endnote/s/technicalsupport?language=en_US