After an auto-update of CWP, I dont know what is the reason I lost the user postfix in mysql
This is how i fixed it, run this SQL as root
GRANT ALL PRIVILEGES ON postfix.* TO 'postfix'@'localhost' IDENTIFIED BY '
YOUR_PASSWORD' WITH GRANT OPTION;
Then, the configuration of postfix file was also changed its location, we need to copy from old location and put it back in right place
sudo chattr -i /usr/local/cwpsrv/htdocs/admin
mkdir /usr/local/cwpsrv/htdocs/admin/include/
mv /usr/local/cwpsrv/htdocs/resources/admin/include/postfix.php /usr/local/cwpsrv/htdocs/admin/include/postfix.php
nano /usr/local/cwpsrv/htdocs/admin/include/postfix.php
put your new password in the file