Error in Nginx monitoring:

Zabbix cannot perform regular expressions for Nginx metrics. This results in metrics not being collected and the system is issuing error messages. Error examples:
Failed: cannot perform regular expression "server accepts handled requests\s+([0-9]) ([0-9]) ([0-9]+)" match for value of type "none" — this indicates that the Nginx status page is unavailable or incorrectly configured.
HTTP/1.1 404 Not Found — the /nginx-status page was not found, indicating incorrect Nginx configuration.
Error with VMware performance data:

Zabbix cannot retrieve virtual machine performance data via the VMware API. This results in data items becoming "not supported". Error examples:
Performance counter data is not available — Zabbix cannot get performance counters for items such as vmware.vm.memory.usage, vmware.vm.storage.writeoio, and others.
Performance counter instance was not found — this error occurs when performance counters on the VMware side are disabled or not configured.
Problems with JSON data conversion:

Error while trying to extract data from JSON:
Failed: cannot extract value from JSON by path "$.searched" — indicates that the data does not match the expected JSON format, which prevents Zabbix from processing the data correctly.
Errors with missing hosts:

Zabbix cannot send a list of active checks because some hosts were not found:
cannot send list of active checks to "host_name": host not found — this indicates problems with host discovery or incorrectly configured agents on these hosts.