When creating the style are you using the Insert Field button when in the correct Reference Type?
Creating a Reference Type and Editing Style can be some of the more complicated taks in EndNote.
I would suggest contacting Technical Support.
They would be able to remote into your machine and take a look or have you send your Reference Type settings and custom style in for them to look at.
Please contact Technical Support directly
1-800-336-4474 option 4 then 1 or
https://support.clarivate.com/Endnote/s/technicalsupport?language=en_US