Hello.
Zabbix 3.0.3 is displaying availability incorrectly.
I have two Windows Server hosts connected directly to the server, one with the 3.0.1 agent and another with 3.0.3 and the availability of both is gray (see attached image in red). But both are successfully communicating with the server, not with errors in the logs and not the server log shows errors. The zabbix_get -k agent.ping returns 1 for both.
I own other Windows server with the 3.0.1 agent connected via proxy (version 3.0.1 too) and this works correctly (see attached image in green).
I believe it is a bug in version 3.0.3 and ask your analysis.

Grateful!

Apologies for English poorly.