… stands for Distributed Denial of Service and is a “distributed” Denial of service (DOS) attack which in turn represents a blockade of service. This is the case when a requested service is no longer available or only available to a very limited extent.
at DDoS -Attacks, it always works in the same way: the server (for example that of a website or an e-mail service) is overwhelmed with so many inquiries that it cannot keep up with answering these inquiries.