Error while connecting to the database

Hi!

the homepage is working but in the overview on wp-admin I see this, how could I fix this I try also to repair but did not work

thx
Peter

Error while connecting to the database
This means either the username or password in your wp-config.php file is not correct, or we cannot contact the database server at dbxxxx-xxxxxxxxxxxxxxx.sql-pro .xxxxxx.net. It may mean that your database server has fallen.

Are you sure you are using the correct username and password?
Are you sure you entered the correct hostname?
Are you confirming that the database server is running?
If you are unsure about these terms, you should probably contact your web host. If you still need help, you can always visit the WordPress Support Forums.