As a workaround, you can add an entry to the routers host file pointing heartbeat.belkin.com to 127.0.0.1. This appears to remove the block. The "block" only affects the DNS server on the device. It will route just fine. You can still get hosts on your network to work as long as you set a DNS server manually, for example using Google's DNS server at 18.104.22.168.
For a statement from Belkin, see https://belkininternationalinc.statuspage.io
In a tweet, Belkin also pointed to this page on its community forum: http://community.belkin.com/t5/Wireless/Belkin-Routers-Internet-Outage/m-p/5796#M1466
Johannes B. Ullrich, Ph.D.