HERE Fleet update layer api is giving error "Provided zipfile expected with one entry, more found."

Question

I am trying to consume one of below CLE API but facing below error. Basically I am trying to add new one record to existing layer. But api is giving below error.

I am trying below api with method POST and form data.

Little help will be highly appreciated.

API : https://fleet.api.here.com/2/layers/modify.json?layer_id=Api_layer_test2&app_id=xyaz&app_code=abv&action=update

METHOD : POST

ERROR:

{
    "issues": [
        {
            "message": "Provided zipfile expected with one entry, more found."
        }
    ],
    "error_id": "73307bf8-ba4e-41e2-941c-7cdbdd65a974",
    "response_code": "400 Bad Request"
}