Can not connect to database

Make sure the mysql user has access to the specific database that you want to be used for wordpress. That’s probably the problem.

it has access to database !

Had the same problem; only way around it was to go through my hosts “applications” (where they have software such as WP available)and install what they had (previous version). I’ll upgrade to the latest release manually. I did see where “localhost” in the config file isn’t “localhost” – so you maybe in that 1% that needs to change that.

99.75% of the time this is due to incorrect info in the config file.
1. Please triple check that you have the user name and password EXACTLY correct. Look especially for spaces at the start or end of the user name (common when cutting and pasting).
2. Talk to your host – triple check that you have the correct hostname. Most use “Localhost” but some use separate DB servers so this needs to be changed.

How I solved this problem.
CPANEL
Go to MySQL Account Maintenance
Check if the database is working.

I eliminated ALL the users.
I add a new user and password and give ALL the privileges to this new user.

The new user should be something like “database_newuser”
The password whatever you created “xfkdjkdsei”

Use this new user and the database will conect without problem.