On my first Lando install I could not enable a database connection. This was my error:
Failed to connect to your database server. The server reports the following message:
SQLSTATE[HY000] [2002] No such file or directory.
I just took the Drupal 9 recipe and used "drupal9" as db credenctials and pass.
When I ran:
lando info
I was able to get some information. This piece gave me the answer:
{ service: 'database',
urls: [],
type: 'mysql',
healthy: true,
internal_connection: { host: 'database', port: '3306' },
external_connection: { host: '127.0.0.1', port: '64423' },
So when I changed hostname from localhost to database the error disappeared and I got to install Drupal.