Server was down for a while for maintenance.

Same server, a quad core Intel(R) Xeon(R) CPU X3430 @ 2.40GHz, with 4 Gb of RAM, and a 250 Gb HDD.

-Went back to Webmin from Plesk.

-Went back to Ubuntu Linux Server Edition 16.04.6 LTS from Windows Server 2012 R2.

-Also upgraded from php5 to php7.