What I'm seeing is, some Book of Faces engineer pushed a router upgrade that went south.
Post or source?
That should be fixable in short order. Unless they screwed up so badly that it broke TFTP or lost access to the console port.
Although I guess enterprises of that size have tools for mass/aggregate management of routers and ain't going to do them onesy-twosey. So something fundamentally wrong could screw up a boatload of them at once. And then you've got to work your way up the chain from the first device that's actually accessible at a root level in a tree configuration.
Without more to go on than the length of the outage, I'm thinking something screwed up with their internal DNS. Rebuilding tables and propagating the changes can take time.
Not a big FB fan, but it's useful to keep in touch with family, and pushing updates out for Mrs. Dual's funeral arrangements. So I hope this is fixed soon.