PHP Curl error HTTP/2 stream 0 was not closed cleanly: PROTOCOL_ERROR (err 1)

Question

I am trying to hit an API from one server to another and getting this response in curl_error($curl); HTTP/2 stream 0 was not closed cleanly: PROTOCOL_ERROR (err 1). Frequency of getting this error message is low, out of 10 attempts 1 to 2 times.

But why i am getting this error, is any specific reason that i am missing?

my Curl code is:

$data = http_build_query(array('param1' => 'test','status' => 'Success'));
$curl = curl_init(); 
curl_setopt($curl, CURLOPT_URL, "server api link");
curl_setopt($curl, CURLOPT_POST, 1);
curl_setopt($curl, CURLOPT_POSTFIELDS, $data);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);

$server_output = curl_exec($curl);
if (curl_error($curl)) {
    $error_msg = curl_error($curl);
}

print_r($error_msg);
curl_close($curl);

Query is same as asked at this link curl php HTTP/2 stream 0 was not closed cleanly

Asking it again as no solution found in previous link, even not at any other locations.

Answer 1

I ran into this exact same issue and the comment from @CodyKL actually solved it in my case so I figured I would turn it into an answer for others to refer to.

Short answer:

Add the following line to your curl request and all shall be solved

curl_setopt($curl, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_1);

Slightly Longer Answer:

Since curl 7.62.0 the default option is: CURL_HTTP_VERSION_2TLS

Before that the default used to be: CURL_HTTP_VERSION_1_1

Some older APIs etc. don't appear to be compatible with the latest HTTP version. The newer version of CURL will use this protocol by default and as a result will fail. This can cause some rather confusing behaviour because a script that works on one machine may not necessarily work on another. To maximise compatibility you should ideally specify CURLOPT_HTTP_VERSION for curl requests to older servers which don't support CURL_HTTP_VERSION_2TLS.