Hi himanshusinghal,Thank you for your response. I tried to increase the Response Buffer Size, then click Save. I got a request error as following:

Hi, Umeshsondhi Thank you for your reply. I have read the article you mentioned.  In localhost, I do not use a dispatcher. It seems that a blank page would always be returned by Publish for invalid url request. I don't know how this blank page is created.

Update for the curl command: I get 200 status for both the valid and invalid url request.Response for requesting the valid url : http://localhost:4503/content/myproject/en/search-results.htmlHTTP/1.1 200 OKDate: Thu, 29 Aug 2019 21:45:38 GMTX-Content-Type-Options: nosniffSet-Cookie: cq-authoring-mod...

I never get a 404 response from the AEM, either in Author or in Publisher. That is very strange.

I am not able to get the 404 response when running a curl command to request a non-existent page. Nothing shows up in the terminal, however, I am able to get the correct page for a valid url using curl.For example, requesting http://localhost:4503/content/myproject/en/search-results shows the html p...

"/content/myproject/en/page-not-found.html" is a custom 404 error page.

yes, I created a 404.html and ResponseStatus.java under /apps/sling/servlet/errorhandlerIn the 404.html, the code is as:<sly data-sly-use.responseStatus="apps.sling.servlet.errorhandler.ResponseStatus">    <sly data-sly-resource="/content/myproject/en/page-not-found.html"></sly></sly>The code in Res...

Sorry, a typo. The response is blank page.

I never got the default 404 not found page working in my local author and publish instances. If the request url is invalid, the response would be a black page with 0 content length, while the HTTP status code is 200. Anyone met with the same problem?

Thank you for your response. I tried the custom error handler, but the results are the same. The aem just returns blank page with 200 status code even if the request url is invalid. Not sure what is wrong?