RDS Postgres 15.2 password authentication failed

If you're using Engine 15 or higher:

When setting up a database in RDS, the default parameter group for PostgreSQL 15 (default.postgres15) is used. However, if you need to change the 'rds.force_ssl' parameter, which isn't editable in the default.postgres15 group, you'll need to create a new parameter group for PostgreSQL 15, allowing you to make edits.

Here's how you can do it:

1. Create a New Parameter Group: Go to the RDS console, navigate to the Parameter groups section, and click on "Create parameter group." Select "PostgreSQL" as the family, choose version 15, and provide a name for your new parameter group.

2. Modify the 'rds.force_ssl' Parameter: Select the newly created parameter group, locate the 'rds.force_ssl' parameter, and change its value from 1 to 0.

3. Apply the Parameter Group to Your Database: Go to the database configuration tab, select the "DB instance parameter group" option, and switch from the default group to the new one you created.

4. Reboot the Database: After applying the new parameter group, reboot the database instance to apply the changes.

After making these changes, you should be able to connect to your PostgreSQL database instance without requiring SSL.

Or you can also try using this connection string for the password authentication. Here's how you can modify the psql command to include the password in the connection string:

psql -h <hostname> -U <username> -d <dbname> -W