‪CentOS Linux 7.5.1804 + Plesk Plesk Onyx Version 17.8.11 server. Attempts to exceed outgoing limits for domains, mailboxes and subscriptions in 3 subscriptions. Need to remove spam script. Also why server use so many resourses.

‪CentOS Linux 7.5.1804 + Plesk Plesk Onyx Version 17.8.11 server. Attempts to exceed outgoing limits for domains, mailboxes and subscriptions in 3 subscriptions. Need to remove spam script Need to check possible php spam scripts or whatever will investigate and solve the issue and secure the server. After solution need to monitoring the server' s status for minimum 48 hours to be sure that the problem solved. Also need to be investigated why server uses so many resourses ( 79% CPU and 84% Real memory) when the traffic is very low!! Need possible ngnx & Apache 2 configuration check. Kernel and CPU Linux 3.10.0-862.3.2.el7.x86_64 on x86_64 Processor information Intel(R) Core(TM) i7-7700 CPU @ 3.60GHz, 8 cores Real memory 61.09 GB total / 51.49 GB used Need full written instructions/ commands how I can investigate and solve similar issues in the same Plesk server or in my back up plesk server too.