reCAPTCHA v3 vb.net Uncaught (in promise) null

Question

Error in console

I'm trying to add a captcha to a VB.net page. The only explanation is Uncaught (in promise) null? I added a label which I have in the script but wasn't on the page and the error goes away but it still doesn't work? By the way, I do get the Are you a robot message if I don't check but if I do check, it just reloads the page and doesn't continue the code in the button click event?

My code:
Script:

var your_site_key = 'xxxxxxxxxxxxxxxxxx';
    var renderRecaptcha = function () {
        grecaptcha.render('ReCaptchContainer', {
            'sitekey': 'xxxxxxxxxxxxxxxxxx',
            'callback': reCaptchaCallback,
            theme: 'light', //light or dark
            type: 'image',// image or audio
            size: 'normal'//normal or compact
        });
    };
    var reCaptchaCallback = function (response) {
        if (response !== '') {
            document.getElementById('lblMessage1').innerHTML = "";
        }
    };

Design view:

<div id="ReCaptchContainer"></div>
<br/><asp:Label ID="lblMessage1" runat="server" />

Code Behind:
In button click

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12
    If IsReCaptchValid() Then
        
    Else
    lblMessage1.Text = "Are you a robot?"
        Return
    End If
  

Function:

    Public Function IsReCaptchValid() As Boolean
    Dim result = False
    Dim captchaResponse  = "g-recaptcha-response"
    Dim secretKey = "xxxxxxxxxxxxxxxxxxx"
    Dim apiUrl = "https://www.google.com/recaptcha/api/siteverify?secret={0}&response={1}"
    Dim requestUri = String.Format(apiUrl, secretKey, captchaResponse)
    Dim request = CType(WebRequest.Create(requestUri), HttpWebRequest)

    Using response As WebResponse = request.GetResponse()

        Using stream As StreamReader = New StreamReader(response.GetResponseStream())
            Dim jResponse As JObject = JObject.Parse(stream.ReadToEnd())
            Dim isSuccess = jResponse.Value(Of Boolean)("success")
            result = If((isSuccess), True, False)
        End Using
    End Using

    Return result
End Function