If you get error 404 after login to the user panel, then you need to check:
- from the command line check for MySQL for errors, you can use this example
mysql -e "show databases;"
* If you only get an output of databases without any error then all is ok with MySQL.
If you have some errors then you first need to fix them before going to the next step.
- rebuild cwpsrv configuration
Now you should be able to open the user panel, if you still have an issue then you should contact cwp support.