As stated in https://www.zabbix.com/forum/showthread.php?p=176600#post176600

There is no encryption setup for the host. The zabbix agentd conf has nothing on encryption. The server, in version alpha4 keeps saying "A TLS connection is configured to be used with agent but support for TLS was not compiled into server." while a clear "NONE" is indicated in the encryption column.

The remote command to execute is /etc/init.d/apache2 restart once swap % usage has reached critical levels. This is done via an action on a specific trigger

I have tried cloning host, creating manually, changing agent configuration and version, I have allowed root to no avail.