LinkedIn Share API 'ugcPosts' response 504 gateway timeout from PHP(Wordpress) - php

Question

I'm using wordpress to shared my post into linkedIn. For this i'm using https://api.linkedin.com/v2/ugcPosts API. But this API response return 504 gateway timeout.
In previous step when i called another API to get access token, its easily got the access token. But when I wanted to create a share using ucPosts POST api request it providing gateway time out.
My requested code here.
Please any one help me.
Tried from localhost apache server(PHP, wordpress)
$params = '{
"author" : "urn:li:person:'.$linkedInAppCredentials->get_user_URN().'",
"lifecycleState" : "PUBLISHED",
"specificContent" : {
"com.linkedin.ugc.ShareContent" : {
"shareCommentary" : {
"text" : "'.$message.'"
},
"shareMediaCategory" : "NONE"
}},
"visibility" :"PUBLIC"
}';
$headers = '{
"Content-Type": "application/json",
"X-Restli-Protocol-Version": "2.0.0",
"x-li-format": "json",
"Connection": "Keep-Alive",
"Authorization": "Bearer '.$linkedInAppCredentials->getAccessToken().'"
}';
$requestedUrl = "https://api.linkedin.com/v2/ugcPosts?oauth2_access_token=".$this->getAccessToken();
$requestBody = array(
'headers' => $header,
'timeout' => 3600,
'body' => $params
);
$result = wp_remote_post($requestedUrl, $requestBody);
Response:
[body] => {"message":"Request timed out","status":504}
[response] => Array
(
[code] => 504
[message] => Gateway Timeout
)

Answer 1

Request timeout may be happening because LinkedIn is not able to parse the request body. So it might be a good idea to convert the requestBody to a JSON string. Giving a proper JSON input worked for me I was having the same problem.
As was happening with another person:
https://stackoverflow.com/a/56786205/12578136