Server Placed In Rescue Mode Due To Anti-Hacking Fix

I have a soyoustart server that was placed in rescue mode for the following reason: As your server SERVER NAME HERE is presenting too great a threat to our network, we had no choice but to place it in 'rescue FTP' mode. An email containing a username and password has been sent to you so that so you can easily retrieve any data still located in the storage space. Please do not hesitate to contact our technical support so that this situation does not become critical. You can find the logs brought up by our system below which led to this alert. - START OF ADDITIONAL INFORMATION - Attack detail : 32Kpps/238Mbps dateTime srcIp:srcPort dstIp:dstPort protocol flags bytes reason 2018.07.25 11:26:40 CEST ip-address-here:58899 [login to view URL] TCP SYN 960 ATTACK:TCP_SYN SAME LINE OVER AND OVER... I need to get this server back online. I can provide the rescue mode info for SSH. I need you to review the logs, see what is going on and fix it so that this is no longer an issue and I can get the server back online ASAP. In addition please be prepared to make any additional changes to harden the server to prevent issues such as this. Thanks