Why is the message truncated when sent via vk api/curl (PHP)?

Question

PHP

Greetings. Here is my code for sending a message via vk API + curl:

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, 'https://api.vk.com/method/messages.send');
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query(['peer_id'=>$peer_id, 'message'=>$message, 'v'=>$v, 'access_token'=>$access_token]));
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

$response = curl_exec($ch);
curl_close($ch);

When sending large messages (4.5-5 thousand characters), I receive only a truncated message, while vk does not return any errors. I get 4090 characters (although it used to come in less, not always 4090). I tried to send my message through the VK site - everything works fine and is not cut off. The documentation does not say anything about limiting the amount of text. What is my problem?