The ProtonMail was still unreachable at the time of writing this article.
The DDoS attack on ProtonMail started somewhere on Tuesday morning.
We are experiencing a DDOS attack and some of our services will be unavailable.
We will post updates on Twitter as we have more info.
It said that the DDoS attack which hit ProtonMail servers, came in four different attacks.
Since there was no letup between this attacks, the datacenter could not recover from the attack.
Despite our best efforts, our infrastructure is still under heavy attack.
We will continue trying to restore services and post updates.
After explaining what a DDoS attack is, it continues: The attackers began by flooding our IP addresses.
That quickly expanded to the datacenter in Switzerland where we have our servers.
In the process of attacking us, several other tech companies and even some banks were knocked offline temporarily.
ProtonMail also stated that the DDoS attack has not compromised their email security in any way.
All user data is fine and safe.
source: www.techworm.net