Unfortunately, the machine upon which the repository for Debian-r is hosted had a catastrophic raid failure on Tuesday, October 20th. The archive will be rebuilt in the coming weeks and will be made available as that rebuild happens.
If you have any questions or concerns, feel free to contact me at firstname.lastname@example.org
The Debian Project has kindly agreed to host the main mirror and dak code to run debian-r. If you use Debian-R, consider contributing time and/or money to the Debian project.