попробуй wp_remote_post/wp_remote_get
сам запрос проходит, но в body
[body] => {"status":false,"errorCode":400,"requestId":"cc489e2f-b503-4734-8082-ffcff7c3c086","response":{"statusReason":"The request can't be understood by the server due to malformed/invalid input.","i18nMessageKeyAvailable":true,"i18nMessageKey":"400"}}