ILOM with firmware 5.0.x and creating users for SNMP v3

Hi

I am unable to create snmp v3 user , utilizing the restapi interface. I tried to use curl and Insomnia.

curl -k -u username:password -X POST "https://ilo_ip_address/rest/v1/SP/services/snmp/users" -H "accept: application/json" -H "Content-Type: application/json" -d "{ \"user_name\": \"snmpp\", \"authenticationpassword\": \"Welcome123\", \"authenticationprotocol\": \"MD5\", \"permission\": \"ro\", \"privacypassword\": \"Welcome123\", \"privacyprotocol\": \"none\"}"

result :

{

 "error": {

"reason":"Bad Request",

  "code":0,

  "message":"Create failed, deleted. Command Failed"

 }

}

Any Help is appretiated