wp-db.php on line 308

Database connection details is 100% correct! And he gives me this ERROR:

Warning: Cannot modify header information – headers already sent by (output started at /home/webdocs/domains/…/wp-admin/setup-config.php:22) in /home/webdocs/domains/…/wp-includes/wp-db.php on line 308

and below

Error establishing a database connection

This either means that the username and password information in your wp-config.php file is incorrect or we can’t contact the database server at mysql69.zdravljetrade.co.yu. This could mean your host’s database server is down.

I was try manual install, but doesn’t help either.