I have searched this issue on internet but none of them helped me.
Also this one doesn`t:
**chgrp apache /path/to/mydir
chmod g+w /path/to/mydir**
Try with following commands:
This will give you the name of apache user.
ps -ef | grep apache | grep -v grep
In most of the cases the user will be www-data.
Run these command after going into the /frontend/web folder:
sudo chgrp www-data ./assets
sudo chmod g+w ./assets/
Your problem will be solved.