For a long time I was using a CiviCRM form for signing up people to our mailing lists, and doing it using html for the form on a non-CiviCRM page.
I have a memory that there used to be an option in the CiviCRM Profile Settings page to export a html snippet you could cut and paste in this manner. This no longer seems to be there.
The problem is that it has stopped working of late - when I upgraded from 4.7.8 to 4.7.11, though I'm only noticing now. When I submit the form using the CiviCRM page
<CiviCRM Install>/?page=CiviCRM&q=civicrm%2Fprofile%2Fcreate&gid=15&reset=1
it works fine. But when I go to the non-CiviCRM page, which worked previously, it no longer works, and I get the following error:
Sorry but we are not able to provide this at the moment. We can't load the requested web page. This page requires cookies to be enabled in your browser settings. Please check this setting and enable cookies (if they are not enabled). Then try again. If this error persists, contact the site administrator for assistance.
Site Administrators: This error may indicate that users are accessing this page using a domain or URL other than the configured Base URL. EXAMPLE: Base URL is http://example.org, but some users are accessing the page via http://www.example.org or a domain alias like http://myotherexample.org.
Error type: Could not find a valid session key.`
Any ideas? I've checked all the Resource URLS and they seem fine. I've checked the html code and, again, it works fine on the CiviCRM generated page but not on the static HTML page.
I'm using 4.7.12 on Wordpress 4.6.1.