cURL error 28: Operation timed out after 2000 milliseconds with 0 bytes received during registration in Laravel 5.4

I am building a laravel 5.4 app. When I fill in the registration form and submit, I get the error below:

ConnectException in CurlFactory.php line 186: cURL error 28: Operation timed out after 2000 milliseconds with 0 bytes received (see http://curl.haxx.se/libcurl/c/libcurl-errors.html)

What causes this error and how can I fix it.

My routes:

Route::get('auth/register', 'Auth\RegisterController@showRegistrationForm');
Route::post('auth/register', 'Auth\RegisterController@register');

I am using Google reCaptcha on the registration form. Below is a more detailed error at CurlFactory::createRejection(object(EasyHandle), array('errno' => 28, 'error' => 'Operation timed out after 2000 milliseconds with 0 bytes received', 'url' => 'https://www.google.com/recaptcha/api/siteverify', 'content_type' => null, 'http_code' => 0, 'header_size' => 0, 'request_size' => 683, 'filetime' => -1, 'ssl_verify_result' => 0, 'redirect_count' => 0, 'total_time' => 1.806389999999999940172301648999564349651336669921875, 'namelookup_time' => 0.004355999999999999629241020926428973325528204441070556640625, 'connect_time' => 0.481848999999999971777242535608820617198944091796875, 'pretransfer_time' => 1.8063789999999999569268993582227267324924468994140625, 'size_upload' => 496.0, 'size_download' => 0.0, 'speed_download' => 0.0, 'speed_upload' => 274.0, 'download_content_length' => -1.0, 'upload_content_length' => 496.0, 'starttransfer_time' => 0.0, 'redirect_time' => 0.0, 'redirect_url' => '', 'primary_ip' => '41.202.206.172', 'certinfo' => array(), 'primary_port' => 443, 'local_ip' => '192.168.433.104', 'local_port' => 49153))