Application runtime path "work path" is not valid. Please make sure it is a directory writable by the Web server process.

CException

Application runtime path "/var/www/html/demo/protected/runtime" is not valid. Please make sure it is a directory writable by the Web server process.

add write permissions to a process, for example set permissions to 775 on runtime directory.

Hi Mohsin

if you using windows change permission under properties of that folder check all the checkboxes, if you linux or mac open up your terminal and type following

chmod -R 775 your/app/directory/

Make sure that you have a directory named runtime inside backend directory, if doesnt exist simply make a new folder named runtime. Then check it.