Microsoft Translation API for Winform

I'm trying to use the Microsoft Translation API in VB.Net, I'm using the Microsoft sample codes (I converted the code from C# to VB.Net), it was working fine until a month ago, but now, it's giving an error.
Does anyone know the solution for this?
Thanks in advance

The code I used:

Private Async Sub ArabicTranslation()  
    Dim route As String = "/translate?api-version=3.0&to=ar"  
    Dim textToTranslate As String = txtProductName.Text  
    Dim body As Object() = New Object() {New With {Key .Text = textToTranslate}}  
    Dim requestBody = JsonConvert.SerializeObject(body)  
    Using client = New HttpClient()  
        Using request = New HttpRequestMessage()  
            request.Method = HttpMethod.Post  
            request.RequestUri = New Uri(endpoint_var & route)  
            request.Content = New StringContent(requestBody, Encoding.UTF8, "application/json")  
            request.Headers.Add("Ocp-Apim-Subscription-Key", key_var)  
            request.Headers.Add("Ocp-Apim-Subscription-Region", region_var)  
            Dim response As HttpResponseMessage = Await client.SendAsync(request).ConfigureAwait(False)  
            Dim result As String = Await response.Content.ReadAsStringAsync()  
            Dim deserializedOutput As TranslationResult() = JsonConvert.DeserializeObject(Of TranslationResult())(result)  
            For Each o As TranslationResult In deserializedOutput  
                For Each t As Translation In o.Translations  
                    txtArabicName.Text = t.Text  
                Next  
            Next  
        End Using  
    End Using  
End Sub