'Response for preflight is invalid (redirect)' error

Question

I am trying to post an API.

Here is my code:

function update(object){
    var data = '<roblox xmlns:xmime="http://www.w3.org/2005/05/xmlmime"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:noNamespaceSchemaLocation="http://www.roblox.com/roblox.xsd"
       version="4">
       <External>null</External><External>nil</External>
       <Item class="StringValue" referent="RBX0">
            <Properties>
                <string name="Name">Notifications</string>
                <string name="Value">'+JSON.stringify(object)+'</string>
            </Properties>
       </Item>
    </roblox>'

    $.post("https://data.roblox.com/Data/Upload.ashx?type=Model&assetid=436257202&length="+data.length,data)

}

update({name:'test'})

But it shows error in console:

XMLHttpRequest cannot load https://data.roblox.com/data/upload.ashx?type=Model&assetid=436257202&length=406. Response for preflight is invalid (redirect)

I think the data is correct, but I am not sure why this error has arisen

Solution

Just piggybacking off of Amazing Aaron's answer, I had a similar issue and can confirm that it was the URL. Try changing all of the cases of http to https. This should resolve it.