after upgrade from 5.2 to 5.7, cannot create node, error 403

Hi,

I just upgrade my testing site from d5.2 to d5.7.

then i cannot create any node. after clicking sumit button, it always show me

"
You are not authorized to view this page
You might not have permission to view this directory or page using the credentials you supplied.

--------------------------------------------------------------------------------

If you believe you should be able to view this directory or page, please try to contact the Web site by using any e-mail address or phone number that may be listed on the devportal3 home page.

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HTTP Error 403 - Forbidden
Internet Explorer
"

thanks