Steps to reproduce:

1. Disable remote zabbix agent to trigger host unavailable
2. Wait for discord webhook message

Result:
Nothing gets posted to Discord due to an API version error thrown by the Discord API.

See this log:
1214:20200714:201614.317 temporarily disabling Zabbix agent checks on host "server.domain.tld": host unavailable
1236:20200714:201637.523 [ Discord Webhook ] FAILED with response: {"message": "Invalid API version", "code": 50041}
1236:20200714:201637.523 [ Discord Webhook ] ERROR: Invalid API version. For more details check zabbix server log.

See memory dump...
Expected:
Discord message from the alert that was generated.