Having the correct HTTP Headers is important for a page to rank and this tool will inform you what header your page is returning. To use the header checker, simply enter your URL and you will be told the code.
Here is a list of acceptable common codes that the H checker tool might return:
301 Permanent Redirect - Given when you use a redirect that is SEO friendly
200 OK - This is what you should be looking for. This is a normal page response.
Here is a list of some you should avoid:
404 Not Found - Given when a page doesn't exist
302 Temporary Redirect - Given when a only a temporary redirect is used.
403 Forbidden - Given when access to the page is denied
401 Unauthorised - Given when access to the page requires you to login
500 Internal Server Error - Given when the server encounters an error processing the page.
Once you have used the header check tool and viewed the HTTP response code, you can decide if it needs changing.