I will paste it here for anyone faceing same problem:
On some machines with Mojave, attempting to use the EndNote CWYW tools may result in returning to the EndNote library, or an Error message.
Mojave includes new Security & Privacy functions which can prevent EndNote from being able to correctly automate. To correctly set these options... 1) Go into the Apple menu 2) Click System Preferences 3) Click Security & Privacy 4) Click the Privacy tab (along the top) 5) Click the Automation options, along the left. 6) Here, make sure that both "Microsoft Word" and "EndNote X#" are both turned on. With this automation turned off, the Cite While You Write functions will not work.