Upgrade to 2.6.x fails with refused connections

[MLNW]

I host Heimdall on a Kubernetes cluster. It is running in version 2.5.8 but when I upgrade to 2.6.0 or 2.6.1 the browser shows

In the container I see the same errors spammed quite frequently:

  SQLSTATE[HY000] [2002] Connection refused (Connection: mysql, SQL: select table_name as `name`, (data_length + index_length) as `size`, table_comment as `comment`, engine as `engine`, table_collation as `collation` from information_schema.tables where table_schema = 'forge' and table_type in ('BASE TABLE', 'SYSTEM VERSIONED') order by table_name)

  at /app/www/vendor/laravel/framework/src/Illuminate/Database/Connection.php:829
    825▕                     $this->getName(), $query, $this->prepareBindings($bindings), $e
    826▕                 );
    827▕             }
    828▕
  ➜ 829▕             throw new QueryException(
    830▕                 $this->getName(), $query, $this->prepareBindings($bindings), $e
    831▕             );
    832▕         }
    833▕     }

  1   [internal]:0
      Illuminate\Foundation\Application::Illuminate\Foundation\{closure}()

      +19 vendor frames
  21  /app/www/app/Providers/AppServiceProvider.php:165
      Illuminate\Support\Facades\Facade::__callStatic()

   Illuminate\Database\QueryException

  SQLSTATE[HY000] [2002] Connection refused (Connection: mysql, SQL: select table_name as `name`, (data_length + index_length) as `size`, table_comment as `comment`, engine as `engine`, table_collation as `collation` from information_schema.tables where table_schema = 'forge' and table_type in ('BASE TABLE', 'SYSTEM VERSIONED') order by table_name)

  at /app/www/vendor/laravel/framework/src/Illuminate/Database/Connection.php:829
    825▕                     $this->getName(), $query, $this->prepareBindings($bindings), $e
    826▕                 );
    827▕             }
    828▕
  ➜ 829▕             throw new QueryException(
    830▕                 $this->getName(), $query, $this->prepareBindings($bindings), $e
    831▕             );
    832▕         }
    833▕     }

  1   [internal]:0
      Illuminate\Foundation\Application::Illuminate\Foundation\{closure}()

      +19 vendor frames
  21  /app/www/app/Providers/AppServiceProvider.php:165
      Illuminate\Support\Facades\Facade::__callStatic()

I'm surprised to see mysql here. Did I miss an upgrade step?

[KodeStar]

Not seen that before, what do you have in your .env?

[LinuxServer-CI]

This issue has been automatically marked as stale because it has not had recent activity. This might be due to missing feedback from OP. It will be closed if no further activity occurs. Thank you for your contributions.

[MLNW]

Not seen that before, what do you have in your .env?

APP_URL=https://heimdall.my.domain
FORCE_HTTPS=true

Sorry for the long delay. These are the values in my .env. The FORCE_HTTPS one needs to be there otherwise we get errors in the browser regarding a mix of HTTP and HTTPS traffic. The instance sits behind a reverse proxy that handles SSL termination.

[LinuxServer-CI]

This issue has been automatically marked as stale because it has not had recent activity. This might be due to missing feedback from OP. It will be closed if no further activity occurs. Thank you for your contributions.