I face this error. It seems due to the presence of extensions in import file names.
The library generating my schema uses ".mjs" files of graphql module, whereas graphql-query-complexity uses ".js" ones, and so graphql module believe that there are 2 different versions of it used.

For instance:

	import {
	  getArgumentValues,
	  getDirectiveValues,
	  getVariableValues,
	} from 'graphql/execution/values.js';

should be replaced with

	import {
	  getArgumentValues,
	  getDirectiveValues,
	  getVariableValues,
	} from 'graphql/execution/values';