I have a long-standing Rails app running on Mac OS X (apache2). The set-up uses Apache virtual hosts and Passenger. The Rails app also uses HTTP Basic Authentication.

I need to migrate the app from one url domain to another - with some overlap of both domain names being accessible simultaneously for a period.

To do this, I've added the new domain name as a ServerAlias of the existing domain name in the Passenger Virtual Host config.

I can now Browse the Rails app using both the legacy url, and the new url from any of Safari, Chrome, Firefox, or Internet Explorer.

I can also 'HTTP post' updates to the Rails app using Safari, Chrome, or Firefox. All good.

Except, attempts to post updates from Internet Explorer result in the Rails app rejecting the update,

The Rails app log contains the message,

ActionController::InvalidAuthenticityToken (ActionController::InvalidAuthenticityToken):

I have other domains & aliases working just fine on this same machine.

Any suggestions as to what is causing the Rails app to reject posts from IE would be appreciated.