Changing document root makes websites always ask for FTP details

Hi guys, I have a virtual machine running Centos 7 & webmin. I mounted a disk to location /mnt/data/ . Then I changed document root of Virtualmin from /home/ to /mnt/data/ (Go to Virtualmin > System Settings > Virtualmin Configuration > Default for new domains > Home directory base ).

After changing document root, any websites that I put in the new location would ask for FTP details whenever I wanted to update plugins or WP core. This is very annoying. Do you have any idea how to fix this please? Thanks