Expected application/json response, got text/html after moving to web server

[yodyyyy]

I've problem with getting error "Expected application/json response, got text/html ". On my localhost it works well but not from web server. I'm running Pl*sk and base with FatFreeFramwork, tried to switching php version but nothing happens, even to put "curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);" into broker.php as @petitbx said. But for php 7.0 i got this error "Broker didn't send a session key".
Thx

php 7.1

php 7.0.15

[jasny]

The error is pretty explicit. The Broker didn't receive JSON from the server. Maybe the URL is misconfigured or there is somekind of server error. I can't tell. You need to debug to see what the server has send.

[yodyyyy]

i think the most problem with getallheaders(), as example running with PHP-FPM. So maybe you must put this code on your script

public function getallheaders() {
    $headers = [];
    foreach ($_SERVER as $name => $value) {
        if (substr($name, 0, 5) == 'HTTP_') {
            $headers[str_replace(' ', '-', ucwords(strtolower(str_replace('_', ' ', substr($name, 5)))))] = $value;
        }
    }
    return $headers;
    }

thank you, sorry for bad english

[awnali]

I got the same error while integrating it with Laravel 5.4. This is how i solved it:
Go to Login method of Jasny\SSO\Server class, core library (must be in vendor folder). change last line to, return $this->userInfo();
Then go to userInfo method and change the last line to: return $user;

Now return from your controller with json header, for example in case of laravel i did:
return response()->json([ 'user' => $user ]);