DNS is a pain in the neck. My ISP’s primary nameserver went down yesterday (which may not be your yesterday – it depends how quickly the DNS issues get resolved as to when you will see this) which wouldn’t ordinarily cause a problem. What did cause a problem was that I’d got the address of the seocondary nameserver wrong in the DNS registry, so as soon as the primary went down (and computers should have started using the secondary) the domain disappeared, leaving only a pair of smoking boots behind.
Of course, I never noticed the duff configuration on the domain since the primary DNS server has been very reliable over the last few years. That’ll teach me, I guess.
Anyway, yesterday, I corrected the registry’s nameserver data, and this morning (I’ve checked) the internet has caught up with that change, but unfortunately things are still broken as I wait for the DNS caching servers to all consider the data they hold to be too old and re-query for it. Until that point, I can’t be emailed, nor can the website be resolved.
When you can read this, the problems are over.