migrating rev 2.3.1 on the same vps but different environment from dev to live issue

HI

i have a problem with migrating the 2.3.1 revo from the development site to the live site on the same vps server.

I have:

ensured that the core/cache folder the contents have been manually deleted.
folder/file permissions have been checked and are ok

checked all the config files and .htaccess file to ensure that any unc location is updated to the new location.

i re copied the setup folder from the original installation and copied across, when i attempted to run the setup via url it showed a website un available message.

so im confused as to what to do next.

Can you verify the MySQL details are correct, and have the necessary permissions?