Improve auth error handle - more clear.
Improve auth error handle - more clear.

alexanderzobnin/grafana-zabbix,alexanderzobnin/grafana-zabbix,alexanderzobnin/grafana-zabbix,xiaohuiz/grafana-zabbix,alexanderzobnin/grafana-zabbix,alexanderzobnin/grafana-zabbix,xiaohuiz/grafana-zabbix,alexanderzobnin/grafana-zabbix