PassiveCheck by curl with exit code 56

Here we use PassiveCheck by curl to directly submit a testing alarming, but feedback with nothing in Icinga2 web console, also has no output in command side. But when check curl return code by “echo $”, it returns 56. I think our Icinga2 server hasn’t handle it correctly. Is there any log to check the detial root cause?

curl -k -s -u passiveCheck:“xxxxxxxxxxxxx” -H ‘Accept: application/json’ -X POST ‘!check_user_resolvable’ -d ‘{ “type”: “Service”, “exit_status”: 2, “plugin_output”: “test result”}’

Does the user have the right permissions?
check under /etc/icinga2/conf.d/api-users.conf on your icinga master node (