Here's a more detailed exception stack trace...
Whoops, looks like something went wrong.
Controller "PCS\PcsDownloadController::initDownload()" requires that you provide a value for the "$request" argument. Either the argument is nullable and no null value has been provided, no default value has been provided or because there is a non optional argument after this one.
in ArgumentResolver.php (line 78)
at ArgumentResolver->getArguments(object(Request), array(object(PcsDownloadController), 'initDownload'))
in HttpKernel.php (line 145)
at HttpKernel->handleRaw(object(Request), 1)
in HttpKernel.php (line 68)
at HttpKernel->handle(object(Request), 1, true)
in Application.php (line 496)
in Application.php (line 477)
in store.php (line 21)
at require('/Volumes/Data HD/Personal/_git/travelblog.ws/marketting/pcs/store.php')
in setup.php (line 147)
After some debugging it turned out that I was missing the following line from my controller class:
It was as simple as that!