When your Disk Space is Full, cPanel completely stops working and starts throwing errors on logins(Refer Below), so Logging into the WHM and check out via “List Accounts” is not an option.
When you cPanel installation shows such errors, It is time that you follow the guide and solve your issue –
All the userdata in cPanel(Files and Folders) are stored in the /home/ directory and it is one of the most obvious reason for cPanel for throwing above error.
To check which users are using the most space Run this command once you have logged in to SSH –
du -hsx /home/* | sort -rh | head -10
It will take some time to show up the result of Top 10 Disk Hoggers on your Shared cPanel server.