I've upgraded from 4.4 to 4.6.10 on Drupal 7.41. I'm getting the following issue when attempting to make a contribution:
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 adminstrator 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: ...
Error type: Could not find a valid session key.
I didn't have this problem before updating to 4.6.10.
I have cookies enabled.
I have confirmed that the Civi and Drupal base URLs are the same and match what is in the address bar of my browser.
Drupal caching is currently disabled.
I have a user 0 in my Drupal database.
Finally and this is the weird thing, when I get the error if I click the back button and resubmit the form it works fine.
Does anyone have a solution or work around for this problem?
Updates
Turns out while the message references sessions it has to do with the contribution page losing the ID but it's an issue with the payment plugin.