Document Upload in Custom Module

Hi,
I am trying to upload document in my Custom Module using suitecrm API V8. My post request for file upload in custom module is:
{
“data”: {
“type”: “custom_module”,
“attributes”: {
“name”: “File Upload Test”,
“document_name”: “File Upload Test”,
“filename”: “test.txt”,
“file_mime_type”: “text/plain”
}
}
}

And its respone is:
{
“errors”: {
“status”: 400,
“title”: null,
“detail”: “Notes module with id abcb1f9a-0ef7-23bf-5816-61f60b039225 is not found”
}
}

I looked up for the issue and then I followed and tried for Notes module. It worked fine but it throws the same error for the custom module.
https://community.suitecrm.com/t/api-upload-file-to-note/67224

What am I missing? Please correct me if I am doing anything wrong!