Problem with Office 365 Federation?

We've been using Office 365 federation with Windows Azure AD for the past few months for a few applications. This morning the following URL now returns a 404 (replacing <domain> with our domain):

https://accounts.accesscontrol.windows.net/<domain>.com/FederationMetadata/2007-06/FederationMetadata.xml

Is this a known issue, I can't find anything in the service dashboard indicating that there's a problem?

Thanks,

Dean