This is similar to what happened to me in January coming back from London when the US Air Traffic system NOTAMS system went down, also supposed to have a "back up" which failed to perform.

The conspiracy person that I am suspects that both may have been due to some one hacking into the US and now British systems, perhaps just for "fun", rather than the system just deciding to go down on a Bank Holiday........

But that is just me.

Hope things get fixed soon.