Zabbix loss existing hosts

[o51n]

Hello!

From time to time zabbix starts to lose hosts and consider that they do not exist but they are created and displayed in the web interface.

An example of a created host with an agent at web interface:



Logs from agent on this host:

2021/02/18 14:05:53.833961 [101] no active checks on server [ZABBIX_SERVER_IP:10051]: host [ACC-SBL-Agent] not found

At the same time logs on server:

213:20210218:140453.833 cannot send list of active checks to "HOST_IP": host [ACC-SBL-Agent] not found
210:20210218:140654.836 autoregistration from "HOST_IP" denied (host:"ACC-SBL-Agent" ip:"HOST_IP" port:10050): connection type "TLS with PSK" is not allowed for autoregistration

But when updating the hostname to wrong one in web interface and then back to correct one everything becomse normal.

Also sometimes when I trying update the some host or template in web interface strange happens.

When trying to update some template:

Incorrect trigger expression. Host "Template [TEMPLATE_NAME] does not exist or you have no access to this host

Inability to update is also solving by changing the name of host/template and its becomes ok.

What could be the reasons for what is happening and how can I fix it?

Docker image: "zabbix-server-pgsql:centos-5.0-latest"
Zabbix version: 5.0.1

[Michael C]

I have the same problem. It began after I upgraded from Zabbix 3.x to Zabbix 5.0. It happens if I delete items - old hosts or items - the system still thinks they are there, and if I update a trigger item, for example, the trigger will error : Cannot update trigger

• Incorrect trigger expression. Host "Template TEMPLATE-NAME-HERE" does not exist or you have no access to this host.

This occurs whenever I update anything that once was associated with a deleted host.

Time to dig into the DB...