How to solve "Yii php framework Application runtime path is not valid.”

Usually, this problem is protected folder on linux or might have SELinux turned on.

First solution (Folder protected)
$chmod 755 /path/to/runtime

or

$chmod 777 /path/to/runtime

if its not work, try second solution (SELinux turned on)

1. Open terminal, login as super user
2. turn SELinux off with command:
$setenforce 0