Converted tables to charts but API link fails generate image

The Charts i have just converted from tables cannot be generated as images,
the API link clicked has to generate an image to be downloaded. but for these links it gives this error_

HTTP Status 500 -


type Exception report


description The server encountered an internal error () that prevented it from fulfilling this request.


	org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.ClassCastException: java.lang.Integer cannot be cast to java.lang.Double org.springframework.web.servlet.FrameworkServlet.processRequest( org.springframework.web.servlet.FrameworkServlet.doGet( javax.servlet.http.HttpServlet.service( org.springframework.web.servlet.FrameworkServlet.service( javax.servlet.http.HttpServlet.service(

and a lot more down.
where am I going wrong?
thank you in advance.