Exception in HttpServlet depends on maxFileSize

I have a servlet and want to restrict uploaded files using the maxFileSize parameter. After some acts I want to send response to my page. It all works with another errors (not maxFileSize).

If the file is big, I get on my page this error:

ERR_CONNECTION_RESET

(but it's not controlled by me). And I can't get adequate text.

In Java when I do String param = req.getParameter("param"); I get the error

java.lang.IllegalStateException: org.apache.tomcat.util.http.fileupload.FileUploadBase$FileSizeLimitExceededException: The field fileList[] exceeds its maximum permitted size of 10485760 bytes.

There is an old issue with the same problem org.apache.tomcat.util.http.fileupload.FileUploadBase$FileSizeLimitExceededException

Java:

    @WebServlet(urlPatterns = "/my_page")
    @MultipartConfig(
            fileSizeThreshold = 1*1024*1024,
            maxFileSize = 10*1024*1024,
            maxRequestSize = 50*1024*1024)
    public class MyServlet extends HttpServlet { 
...
String param = req.getParameter("param"); 
...    
req.setAttribute("infoResult", "File is too big");
req.getRequestDispatcher("my_page.jsp").forward(req, resp);

Javascript:

const xhr = new XMLHttpRequest();
        xhr.open("POST", "${pageContext.request.contextPath}", true);
        xhr.timeout = 10000; 
        xhr.send(formData);

 xhr.onerror = function () {
// I get xhr.status = 0 here and nothing in responseText
        };

xhr.onreadystatechange = function () {
// I get xhr.status = 0 here and nothing in responseText
        };