You would first want to check Preferences > Application tab on the EndNote tab for the URL typed in.
If it is not
http://www.myendnoteweb.com:80/
You would want to change it to the above.
If the change does not help or if it was set correctly then please contact Technical Support:
1-800-336-4474 option 4 then 1
or
https://support.clarivate.com/Endnote/s/technicalsupport?language=en_US