503 Error When Using WebHook API

Hello I am trying to use web hooks in Sandbox to test my website.

The idea is simple, send a post request to my server via webhook whenever a customer is created.

The problem is that I get a 503 error every time and the request never reaches my server. I am using HTTPs on my server and it accepts post requests no problem when I use Postman. I also have it set up so it sends a 201 code when a post request is sent.

I am using the sandbox to test this. Here is my payload:

square-initial-delivery-timestamp: 2022-12-29T02:09:30Z
x-square-signature: z64TNx2z7p6yDeWUMJfDkjw9mXQ=
content-length: 752
square-environment: Sandbox
square-version: 2022-11-16
host: ajd249rdaproject.website:3000
content-type: application/json
x-square-hmacsha256-signature: jrF42OLNhCzV1WdCyJpxf3lPC2gUaXaqhELQ12RpW9c=
user-agent: Square Connect v2

  "merchant_id": "MLSA58W5KV33K",
  "type": "customer.created",
  "event_id": "9594b5a4-3ccc-474d-bba2-91af0957d788",
  "data": {
    "id": "QPTXM8PQNX3Q726ZYHPMNP46XC",
    "object": {
      "customer": {
        "address": {
          "address_line_1": "1018 40th Street",
          "administrative_district_level_1": "CA",
          "locality": "Oakland",
          "postal_code": "94608"
        "birthday": "1962-03-04",
        "created_at": "2022-11-09T21:23:25.519Z",
        "creation_source": "DIRECTORY",
        "email_address": "[email protected]",
        "family_name": "Smorly",
        "given_name": "Jenkins",
        "group_ids": [
        "id": "QPTXM8PQNX3Q726ZYHPMNP46XC",
        "phone_number": "+12126668929",
        "preferences": {
          "email_unsubscribed": false
        "updated_at": "2022-11-09T21:23:25Z",
        "version": 0

Here is a picture of my test request summary:

Not sure how to troubleshoot this or what I am doing wrong. Any tips?