We recently uncovered a strange "feature" of IE. Apparently, it rejects session cookies and client-side cookies coming from URLs with underscores in them. We noticed this while doing some internal testing for our Flash CS4 upgrade.

Anyone who has created an X2O account with an underscore in the subdomain may not be able to login to their X2O client on IE. Similarly, creating projects with an underscore in the project name will affect logins for the generated CMS. X2O currently scrubs names when creating URLs to allow only alphanumerics as well as an underscore.

In the future, we will update X2O to not allow underscores in any generated web sites. For now, just be aware of this current issue in our system.