Event Subscription not working

[mistljo]

I call $yamaha->api('events')->subscribe(); and get this eror:

Fatal error: Uncaught MusicCast\Exception\ErrorException: Invalid Request (A method did not exist, a method wasn’t appropriate etc.) in /var/lib/symcon/scripts/vendor/granddam/php-musiccast-api/src/HttpClient/Plugin/MusicCastExceptionThrower.php:28
Stack trace:
#0 /var/lib/symcon/scripts/vendor/php-http/httplug/src/Promise/HttpFulfilledPromise.php(34): MusicCast\HttpClient\Plugin\MusicCastExceptionThrower->MusicCast\HttpClient\Plugin{closure}(Object(GuzzleHttp\Psr7\Response))
#1 /var/lib/symcon/scripts/vendor/granddam/php-musiccast-api/src/HttpClient/Plugin/MusicCastExceptionThrower.php(38): Http\Client\Promise\HttpFulfilledPromise->then(Object(Closure))
#2 /var/lib/symcon/scripts/vendor/php-http/client-common/src/PluginClient.php(160): MusicCast\HttpClient\Plugin\MusicCastExceptionThrower->handleRequest(Object(GuzzleHttp\Psr7\Request), Object(Closure), Object(Closure))
#3 /var/lib/symcon/scripts/vendor/php-http/client-common/src/PluginClient.php(174): Http\Client\Common\PluginClient->Http\Client\Common{closure}(Objec in /var/lib/symcon/scripts/vendor/granddam/php-musiccast-api/src/HttpClient/Plugin/MusicCastExceptionThrower.php on line 28