Getting an error while accessing the models folder

Warning : SplFileInfo::openFile(/var/www/html/tmp/cache/models/myapp_cake_model_default_scores): Failed to open stream: Permission denied in /var/www/html/vendor/cakephp/cakephp/src/Cache/Engine/FileEngine.php on line 393

i dont know whats happening here… i have added mask=0666 in the app.php for cache also still i am getting this warnings.

Have you followed these instructions on setting permissions? Installation - 4.x