I have created a flow that uses the "Send Http Request to SharePoint" action. In most cases the flow will run without failure, but in rare cases it may fail. The error occurred in the flow is status 400 error, but the actual error returned by the Sharepoint server is status 503. "HTTP Error 503. The service is unavailable."
In this case, "HTTP error 503" is clearly indicated, but the action itself displays "Status Code: 400" and the request cannot be automatically retried. Please improve the flow so that it can reflect the actual error.