When a HTTP request is received error 503 service unavailable

[Will_]

Hello,

I'm currently having a problem with a flow.

I'm linking a Splunk alert set to webhook call to a Power Automate flow that parse the JSON payload to get the data and finally send a message in a Teams chat room with the data. I use the "When a HTTP request is received" trigger for my automated cloud flow.

It looks like that :

Flow

The JSON schema works perfectly fine.

The Splunk alert is triggered but in the logs it says :
STDERR - Error sending webhook request: HTTP Error 503: Service Unavailable

The flow works with a POST call in Postman (from my laptop to power automate).

More weird is that it was working perfectly fine a week ago.

Any idea why the 503 error ? It may come from Splunk but I'm not sure