jQuery and Spring MVC: Problems when using Ajax POST

I have written my first Spring MVC controller. While I have no problems with GET requests, I am still having some issues with POST methods.

This is the code in my controller:

@RequestMapping(value = "/editorsWriters", method = RequestMethod.POST)
    public <HttpServletRequest> ResponseEntity<List<FreelancerContactWriterListView>> getEditorsWriters(
                                                                    @RequestParam int[] languageIds, 
                                                                    @RequestParam int[] summaryGroupIds, 
                                                                    @RequestParam String[] writerStates,
                                                                    HttpServletRequest request, HttpServletResponse response) {

        WriterState[] writerState = Arrays.copyOf(writerStates, writerStates.length, WriterState[].class);
        

        List<FreelancerContactWriterListView> writers = writerService.getActiveWriters(languageIds, summaryGroupIds, writerState)
                                                                    .stream()
                                                                    .map(writer -> this.convertTo(writer))
                                                                    .collect(Collectors.toList());

        
           return new ResponseEntity<List<FreelancerContactWriterListView>>(writers, HttpStatus.OK);
    }

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and this is the JavaScript code:

 $("#search").on("click", function(e) {
            var languages=$("#languages").val();
            var summaryGroups = $("#summaryGroups").val();
            var writerStates = $("#writerState").val();
            
            var myObject = new Object();
            myObject.languageIds = languages;
            myObject.summaryGroupIds = summaryGroups;
            myObject.writerStates = writerStates;

            var myData = JSON.stringify(myObject);

            console.log(myData);

            $.ajax({
                method: 'POST',
                dataType: 'json',
                data: myData,
                url:'/api/pps/contactFreelancers/editorsWriters',
                contentType: "application/json"
            })
            
        });

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This is the JSON sent:

{"languageIds":["1"],"summaryGroupIds":["11"],"writerStates":["PROBATION","REGULAR"]}

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The problem is that I get a POST 404 (Not Found) error in the JavaScript console
POST https://dev1.getabstract.com/api/pps/contactFreelancers/editorsWriters 404 (Not Found)

and the following message in the terminal of my IDE:

2019-07-14 22:49:06,923 DEBUG [BaseControllerExceptionHandler] Page not found for the URL https://dev1.getabstract.com/api/pps/contactFreelancers/editorsWriters with query null: Required int[] parameter 'languageIds' is not present

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So it is reaching or sending the POST to the correct URL, but what am I doing wrong?

Is the way I have created the data wrong?
languages, summaryGroups and writersStates are all arrays and I am putting them together into one JSON.

Thanks for your help

Massimo