grab the password for cyberpanel database from the file
/etc/postfix/mysql-virtual_domains.cf
make sure the MySQL access is working with that password using following command
mysql -u cyberpanel -p
also check the file /usr/local/CyberCP/CyberCP/settings.py it has the same pass as listed /etc/postfix/mysql-virtual_domains.cf
if not , try to reset with the same pass as of in /etc/postfix/mysql-virtual_domains.cf and update the file /usr/local/CyberCP/CyberCP/settings.py
this should fix it