Add line Item

Summary:

/rest/v19/commerce{Stage}{ProcessVarName}{MainDocVarName}/{id}/actions/addLineItem_t

tried this API call from the post man and getting below response.

"title": "Action addLineItem_t doesn't exist or is not accessible in resource commerceDocuments{process name}Transaction for current user."}

May i know what could be the issue for this?

Content (please ensure you mask any confidential information):

Version (include the version you are using, if applicable):

19

Code Snippet (add any code snippets that support your topic, if applicable):