Magento 2 debug controller match

Useful if your custom controller is not firing

Places to check:
vendor/magento/framework/App/FrontController.php

 while (!$request->isDispatched() && $routingCycleCounter++ < 100) {
            /** @var \Magento\Framework\App\RouterInterface $router */
            foreach ($this->_routerList as $router) {
                try {
                    $actionInstance = $router->match($request);
                    if ($actionInstance) {
                        $result = $this->processRequest(

vendor/magento/framework/App/Router/Base.php

  foreach ($modules as $moduleName) {
            $currentModuleName = $moduleName;

            $actionClassName = $this->actionList->get($moduleName, $this->pathPrefix, $actionPath, $action);
            if (!$actionClassName || !is_subclass_of($actionClassName, $this->actionInterface)) {
                continue;
            }

            $actionInstance = $this->actionFactory->create($actionClassName);
            break;
        }