Incoming Webhook - 503 Service Unavaliable

Question

I added a new Incoming Webhook to Teams apparently successfully. But when performing curl, Http code 503 is returned

curl -H 'Content-Type: application/json' -d '{"text": "Hello World"}' https://xxxxxxxx

Body Response: void

Headers Response:

[{"key":"Server","value":"Microsoft-IIS/10.0","description":"Contains information about how the server handles requests.","enabled":true,"disableEdit":true,"info":"Contains information about how the server handles requests."},{"key":"request-id","value":"dd8dffc8-aa88-e29e-02b5-badce3e71b7f","description":"Custom header","enabled":true,"disableEdit":true,"info":"Custom header"},{"key":"Strict-Transport-Security","value":"max-age=31536000; includeSubDomains; preload","description":"Lets websites tell a browser that they should only be accessed via HTTPS.","enabled":true,"disableEdit":true,"info":"Lets websites tell a browser that they should only be accessed via HTTPS."},{"key":"Alt-Svc","value":"h3=":443",h3-29=":443"","description":"Custom header","enabled":true,"disableEdit":true,"info":"Custom header"},{"key":"X-PreferredRoutingKeyDiagnostics","value":"0","description":"Custom header","enabled":true,"disableEdit":true,"info":"Custom header"},{"key":"X-CalculatedFETarget","value":"ROAP284CU004.internal.outlook.com","description":"Custom header","enabled":true,"disableEdit":true,"info":"Custom header"},{"key":"X-BackEndHttpStatus","value":"503","description":"Custom header","enabled":true,"disableEdit":true,"info":"Custom header"},{"key":"X-CasErrorCode","value":"NoAvailableSubstrateServicesEndpoints","description":"Custom header","enabled":true,"disableEdit":true,"info":"Custom header"},{"key":"X-RUM-Validated","value":"1","description":"Custom header","enabled":true,"disableEdit":true,"info":"Custom header"},{"key":"X-RUM-NotUpdateQueriedPath","value":"1","description":"Custom header","enabled":true,"disableEdit":true,"info":"Custom header"},{"key":"X-RUM-NotUpdateQueriedDbCopy","value":"1","description":"Custom header","enabled":true,"disableEdit":true,"info":"Custom header"},{"key":"X-BEPartition","value":"Clique/CLBRAP284CPQ05","description":"Custom header","enabled":true,"disableEdit":true,"info":"Custom header"},{"key":"X-BEPartition","value":"Clique/CLLAMPRD80CPQ03","description":"Custom header","enabled":true,"disableEdit":true,"info":"Custom header"},{"key":"X-FEProxyInfo","value":"CP6P284CA0023.BRAP284.PROD.OUTLOOK.COM","description":"Custom header","enabled":true,"disableEdit":true,"info":"Custom header"}]