Can’t acces WP Admin

I’m having very big issues with my Website: https://seomaniak.ma/

The website home pages is working but all the other linkes are broken with : the same error, https://seomaniak.ma/blog-marketing-digital-maroc/ ( check here)

Error access to WP-Admin: Error establishing a database connection

I re installed WordPress. ( From the ftp )
I tried to check the PHP config folder everything looks fine,

I can’t access to PHP admin neither,

Error Php admin:
#2002 – No such file or directory — Le serveur ne répond pas (ou l’interface de connexion vers le serveur MySQL local n’est pas correctement configurée). (

I’m suing webmin as a control pannel by the way ( version 2.0 )
Operating system Debian Linux 9

Someone can help me here?

The page I need help with: [log in to see the link]