How can I send a file through Form Data in a REST HTTP Request?

Hello everyone!
I have to build a REST service that receives a POST HTTP-request, collect a file from that request in the Form data and then send it in another HTTP Post request through Form Data. However I can't really seem to send the file, and I do not know where it has gone wrong. All I am getting told is that no file is being received from my HTTP Post request. I am reaching the REST Service I am supposed to send the request to, but nothing is being sent.

I would be really thankful if someone could give some insight why nothing is being sent in my request. Thanks beforehand! :)

So, this is my REST-Service that receives the HTTP request:

XData UrlMap [ XMLNamespace = "https://www.intersystems.com/urlmap" ]
{
<Routes>
<Route Url="/TEST" Method="POST" Call="PostHandler" />
</Routes>
}

ClassMethod PostHandler() As %Status
{

set vProfile = %request.Get("profile")

set vFilen = %request.GetMimeData("file")

set classToPostHandler = ##class(Classes.PostClass).%New()

set classToPostHandler.Profile = vProfile

set classToPostHandler.file = vFilen

set status = ##class(Ens.Director).CreateBusinessService("PostHandlerService", .instance)
    #dim response as %DynamicObject
    
    set status = instance.OnProcessInput(classToPostHandler, .response)
    
   if $ISOBJECT(response)
{          Do ##class(%REST.Impl).%SetContentType("application/json; charset=utf-8")
       Do ##class(%REST.Impl).%SetStatusCode("200")
       Do ##class(%REST.Impl).%WriteResponse(response)

       Quit $$$OK
}else
{
Do ##class(%REST.Impl).%SetStatusCode("500")
write "ERROR"
} Quit $$$OK

}

Underneath is my class that is used to transfer "vProfile" and "vFilen" to the Business Service that executes the HTTP Post request:

Class Classes.PostClass Extends %Persistent
{

Property Profile As %String;

Property file As %Stream.FileBinary;

}

Underneath here is the Business Service that executes the HTTP Post request:

Method OnProcessInput(pInput As Classes.PostClass, Output pOutput As %RegisteredObject) As %Status
{
set profile = pInput.Profile

set filen = pInput.file 

set request = ##class(%Net.HttpRequest).%New()
set request.Server = "placeholderurl.url"
set request.ContentType = "multipart/form-data;"
Do request.SetHeader("Accept", "*/*")
Do request.SetHeader("Accept-Encoding","gzip, deflate, br")

Do request.InsertFormData("profile", profile)
Do request.InsertFormData("file",filen) 

set tsc = request.Post("placeholderendpoint")

set response = request.HttpResponse.Data

set code = request.HttpResponse.StatusCode
$$$LOGINFO(response)
$$$LOGINFO(code)
set pOutput = response
Quit $$$OK
}else
{
$$$LOGINFO("ERROR")
}
} Quit $$$OK
}

}