Cordial greeting

A month ago I installed my server Zabbix in a Redhat 7.4 x64 linux a few days ago I noticed a strange behavior I see that in all the hosts only brings me the information of the Zabbix server , is the same data for all the monitors, check lowering the service in one of the hosts but this one is not alert , download the service of agent of my server Zabbix , and all the connections fall down, already I put my problem in the post but I receive no answer would appreciate your collaboration.