Disk IO usage graph is not working

Hello,
I am using CWP PRO. My CPU usage graph is working fine. But the Disk IO is showing 0.

Also disk quotas at accounts login are not showing the usage. What exactly have I to do?

restart quota with: quotaoff -a;quotaon -a

And after that, needs anything a restart? Apache and/or nginx ?

Yes, i also face the same problem. I need a solution for this. If you face problems regarding web hosting then i have solutions.

Finally, I am using CWP PRO with more than 20 websites and I have never enabled quotas.

I can not understand why this is not working.

If you are using a VPS, chances are the KVM kernal does not have quota enabled by default.  Try this:

https://www.interworx.com/support/faq/enabling-quotas-centos7/

I have tried so many VPS hosting companies and quotas never worked. How can I enable them? Is there a global documentation for that?

From where do I start please?

After using VPN its working fine for me

I know that it's not working for few days. I have looked into many solutions online but nothing worked is too complicated.