Heroku successful deploy but receiving error on opening the app

I have deployed a DotNet Core application on Heroku but I m receiving the following error when I'm trying to open the application

fail: ShopApi.Program[0]
      An error occurred while migrating the database.
Npgsql.PostgresException (0x80004005): 28000: no pg_hba.conf entry for host "3.249.151.147", user "ddojar225ki3s4", database "ddojar225ki3s4", SSL off
   at Npgsql.NpgsqlConnector.<ReadMessage>g__ReadMessageLong|194_0(NpgsqlConnector connector, Boolean async, DataRowLoadingMode dataRowLoadingMode, Boolean readingNotifications, Boolean isReadingPrependedMessage)
   at Npgsql.NpgsqlConnector.Authenticate(String username, NpgsqlTimeout timeout, Boolean async, CancellationToken cancellationToken)
   at Npgsql.NpgsqlConnector.Open(NpgsqlTimeout timeout, Boolean async, CancellationToken cancellationToken)
   at Npgsql.NpgsqlConnection.<>c__DisplayClass41_0.<<Open>g__OpenAsync|0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at Npgsql.NpgsqlConnection.Open()
   at Npgsql.EntityFrameworkCore.PostgreSQL.Storage.Internal.NpgsqlDatabaseCreator.Exists()
   at Microsoft.EntityFrameworkCore.Migrations.HistoryRepository.Exists()
   at Microsoft.EntityFrameworkCore.Migrations.Internal.Migrator.Migrate(String targetMigration)
   at Microsoft.EntityFrameworkCore.RelationalDatabaseFacadeExtensions.Migrate(DatabaseFacade databaseFacade)
   at ShopApi.Extensions.MigrateDatabaseExtension.MigrateDatabase[T](IHost webHost) in /src/ShopApi/Extensions/MigrateDatabaseExtension.cs:line 22
  Exception data:
    Severity: FATAL
    SqlState: 28000
    MessageText: no pg_hba.conf entry for host "3.249.151.147", user "ddojar225ki3s4", database "ddojar225ki3s4", SSL off
    File: auth.c
    Line: 496
    Routine: ClientAuthentication

I have added an Add-On for Postgresql.

I am connecting to the database like this :

 services.AddDbContext<DataContext>(optionsBuilder =>
                optionsBuilder.UseNpgsql(Configuration.GetConnectionString("PostgresSqlDatabaseConnection")));

My Connection String

"PostgresSqlDatabaseConnection": "User ID=ddojar225ki3s4;Password=correct_password;Server=ec2-34-242-89-204.eu-west-1.compute.amazonaws.com;Port=5432;Database=ddojar225ki3s4;Integrated Security=true; Pooling=true"

Solution

I had to add SSL Mode=Require; to the connection string.

Be careful NOT to type Required or SSL Mode=SSL.Require