Reports of a major resolution failure on the .DE zone are coming out of Germany. It appears that for about 1.5 hours around lunchtime (in Europe) today, there was a problem with the nameservers used to support the .DE zonefile.
As a consequence, many .DE domains became unavailable causing disruptions to websites, email and other domain-related services. The German registry Denic apparently stepped in very quickly to correct the problem (which they may have caused by mistakenly reloading the zonefile with erroneous data), and the .DE zone now seems to be running normally again.
A statement on the problem has yet to be issued by Denic, but there are bound to be consequences. Denic runs the largest ccTLD in the world and this technical problem probably sets a new record for massive domain name disruptions. It is extremely rare, unheard of in fact, for such widespread disruption to occur at registry level on a major TLD.