Dear Experts ,

We are not able to attach Attachment in existing tickets through REST postman API client for SMAX . 

We are getting below error while updating/add attachments with existing tickets through Postman API Client , Please let me know , where we are getting wrong ..

We have followed below document for reference:-

Attachments - Service Management Automation X (microfocus.com)

Below body parameters we are using 

{
"entities":[
{
"entity_type":"Incident",
"properties":{
"Id":"15705",
"Description": "<p>Test</p>",
"IncidentAttachments":"{
\"complexTypeProperties\":[
{
\"properties\":{
\"id\":\"3737b279-e4b7-4a68-8fee-a2aa96ebef8b\",
\"file_name\":\"test.txt\",
\"file_extension\":\"txt\",
\"size\":\"24\",
\"mime_type\":\"text/plain\",
\"Creator\":\"nks@opentext.com\"
}
}
]
}"
}
}
],
"operation":"UPDATE"
}

Regards,

Jatin