echo "Detailed Inode usage for: $(pwd)" ; for d in `find -maxdepth 1 -type d |cut -d\/ -f2 |grep -xv . |sort`; do c=$(find $d |wc -l) ; printf "$c\t\t- $d\n" ; done ; printf "Total: \t\t$(find $(pwd) | wc -l)\n"

I was facing the issue because the inode usage for my account was exceeded. You can check it from cPanel >> Inode usage.

You can follow below steps to reduce the inode usage -

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1. Remove all files/folders you don’t need.

2. Check the number of cache files you have, applications such as Joomla can generate a lot of cache files; you should regularly check your cache folder and reduce the number of cached files you keep.

3. Make sure you check the mailbox regularly and delete all mails you don't need.

4. Check your cPanel's main email account regularly, the mails for it are kept in:

/home/username/mail/cur
/home/username/mail/new​

where username is your cPanel username. You can manually delete the messages in these folders using cPanel's File Manager.

5. You should also check your email accounts regularly and delete any spam messages from them.

6. If you have email accounts you don't need or use, it would be best to remove them.
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In my case, it was due to the .trash directory. I've removed the directory. It resolved my issue!