Unable to Send/Receive Emails Through RainLoop

I have migrated my cPanel backup to CyberPanel on my VPS and; I am able to see my all past email messages but at present I am unable to Send/Receive any new Emails.
I am looking for some help to fix it, as I am new for CyberPanel & RainLoop that’s why I need help.
Is there any complete tutorials regarding this or how can I diagnose the actual error and to fix it.
I really appreciate for the kind help.