Question : POST error

Can anyone tell me what this error means?   Here's my form tag:

form id="form" name="form" method="post" action="thankyou.html">

The HTTP verb POST used to access path '/xxxx/yyyy/thankyou.html' is not allowed.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Web.HttpException: The HTTP verb POST used to access path ' '/xxxx/yyyy/thankyou.html' is not allowed.

Answer : POST error

you can not post data to an html file,

<form id="form" name="form" method="post" action="thankyou.html">