what is ddos attack?

[wesen]

DDoS or Distributed Denial of Service occurs when an attacker sending a lot of traffic at the server at once, therefore blocking legitimate traffic (and making the site go offline). Further read on how DDoS works and common types of DDoS: https://www.casbay.com/blog/tips-sharing...dos-attack
However, your sites should be fine once they mitigate the attack.