Config values on Docker/Synology not working

[marvelloard]

Though I set all the config values (mariadb runs on 3307 on Synology) I get:

DBIx::Class::Storage::DBI::catch {...} (): DBI Connection failed: DBI connect('database=koha;host=db;port=3306','koha',...) failed: Unknown MySQL server host 'db' (-2) at /home/koha/koha/bin/../Koha/Database.pm line 91. at /home/koha/koha/bin/../Koha/Database.pm line 139

Which means it uses default values I think.
Here's a screenshot of the values.