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What causes an HTTP 405 "invalid method (HTTP verb)" error when POSTing a form to PHP on IIS?

Posted by: admin April 23, 2020 Leave a comment


I have one form in a PHP (5.2.9-1) application that causes IIS (Microsoft-IIS/6.0) to throw the following error when POSTed:

The page you are looking for cannot be displayed because an invalid method (HTTP verb) was used to attempt access.

It’s an HTTP 405 status code. All other forms in the application work, so I believe that the IIS ‘verbs’ setting for PHP pages is correct.

This is a customer’s server, which I have no access to for verifying settings or testing code. All I can do is send the customer replacement files. Other customers on IIS servers have no such issue.

The form is perfectly straightforward:

<form method="post" action="index.php">
    ... fields ... 

What can cause IIS to throw that error on one form only, but work fine on others?

How to&Answers:

I managed to get FTP access to the customer’s server and so was able to track down the problem.

After the form is POSTed, I authenticate the user and then redirect to the main part of the app.


The error was occurring not on the posting of the form, but on the redirect immediately following it. For some reason, IIS was continuing to presume the POST method for the redirect, and then objecting to the POST to /apps/content as it’s a directory.

The error message never indicated that it was the following page that was generating the error – thanks Microsoft!

The solution was to add a trailing slash:


IIS could then resolve the redirect to a default document as is no longer attempting to POST to a directory.


I am deploying VB6 IIS Applications to my remote dedicated server with 75 folders. The reason I was getting this error is the Default Document was not set on one of the folders, an oversight, so the URL hitting that folder did not know which page to server up, and thus threw the error mentioned in this thread.


By any chance have you tried POST vs post? This support article suggests it can cause problems with IIS: http://support.microsoft.com/?id=828726


The acceptable verbs are controlled in web.config (found in the root of the website) in <system.web><httpHandlers> and possibly <webServices><protocols>. Web.config will be accessible to you if it exists. There is also a global server.config which probably won’t. If you can get a look at either of these you may get a clue.

The acceptable verbs can differ with the content types – have you set Content-type headers in your page at all ? (i.e. if your Content-type was application/json then different verbs would be allowed)


I don’t know why but its happened when you submit a form inside a page to itself by the POST method.

So change the method="post" to method="get" or remove action="anyThings.any" from your <form> tag.


It sounds like the server is having trouble handling POST requests (get and post are verbs). I don’t know, how or why someone would configure a server to ignore post requests, but the only solution would be to fix the server, or change your app to use get requests.


I had this issue with a facebook application that I was developing for a fan page tab. If anyone faces this issue with a facebook application then

1-goto https://developers.facebook.com

2-select the application that you are developing

3-make sure that all the link to your application has tailing slash /

my issue was in the https://developers.facebook.com->Apps->MYAPPNAME->settings->Page Tab->Secure Page Tab URL, Page Tab Edit URL, Page Tab URL
hope this will help


As drewm himself said this is due to the subsequent redirect after the POST to the script has in fact succeeded. (I might have added this as a comment to his answer but you need 50 reputation to comment and I’m new round here – daft rule IMHO)

BUT it also applies if you’re trying to redirect to a page, not just a directory – at least it did for me. I was trying to redirect to /thankyou.html. What fixes this is using an absolute URL, i.e. http://example.com/thankyou.html


i had to change my form’s POST to a GET. i was just doing a demo post to an html page, on a test azure site. read this for info: http://support.microsoft.com/kb/942051


We just ran into this same issue. Our Cpanel has expanded from PHP only to PHP and .NET and defaulted to .NET.

Log in to you Cpanel and make sure you don’t have the same issue.


An additional possible cause.

My HTML page had these starting tags:

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">

This was on a page that using the slick jquery slideshow.

I removed the tags and replaced with:


And everything is working again.