Square Webhook 503 Service Unavailable - Just Stopped working

Questions
1

I have been using Webhook and they have been working for Over 1 Year
On the 29/1/2025 at 15:30, I stopped Getting Webhooks from Square
I looked at the Square Webhook Logs and I can Error 503
When I do a Test Webhook Event I get 503 - Service Unavailable
Nothing has changed at this end (No Firewall changed, SSL certificates are Valid)
I need URGENT help as I manage several customers

2

:wave: I’m Square Dev AI, here to help answer your question!
Based on the information you’ve provided, the following documentation will help answer your question:

Additional Documentation

Payments API Webhooks
Refunds API Webhooks
Use Webhooks to Integrate with a Payroll System

If this documentation helped you find a solution, please check the box indicating that this reply solves the problem.
Otherwise one of our Developer Advocates will provide additional assistance shortly.

3

The 503 Service Unavailable error indicates that your server is temporarily unable to handle the request. This could be due to the server being overloaded or down for maintenance. Here are a few things you can check:

  1. Server Overload: Check your server’s resource usage. If your server is experiencing high traffic or is using most of its resources, it might not be able to handle incoming requests, including those from Square’s webhooks.

  2. Server Maintenance: If your server is down for maintenance or updates, it could return a 503 error. Ensure that your server is up and running.

  3. Network Issues: There could be network issues between Square and your server. You can try to diagnose this by checking if your server is accessible from different networks.

  4. Application Errors: If your application running on the server is experiencing errors, it could cause a 503 response. Check your application’s error logs for any issues.

Remember, the issue is temporary and once the server is able to handle requests, you should start receiving webhooks again. If the issue persists, you might need to contact your hosting provider or a network administrator for further assistance.

This answer was reviewed by @Bryan-Square.

4

I seems the TLS version from Square end has changed andis the reason why Webhooks are not working. Can you please advise the TLS version webhooks are using

5

Hello! Square advises using TLS 1.3 or 1.2, although I don’t believe this recommendation has changed recently.

6

The Webhook were correctly received up until 29/1/2025 15:30.
Our HTTPserver is giving this Error:
SSL3__GET_CLIENT:no shared cipher
We have not changed our Listener code, and the Server has not had any Windows Updates