CI not working when used inside REST API Handler

Dear All,

We have a requirement to provide a POST REST API. The API is having 3-4 existing component interfaces. The CI's are already working properly when used in a separate component. But when used within the REST API handler (app package), none of them are working. It says 'Save failed (0,0) App Package.App Package.Class.OnExecute Name:OnRequest PCPC:11032'.

Have created a new permission/role. Added all the CI's permissions to the permission and granted full access. Assigned the permission to role and the role to the user. Still not working.

Please suggest on how to use the CI's within the REST API handlers.