This is what’s working for me, in case anyone is struggling to use AWS SES as SMTP.
# ## Configuring the mailer for AWS SES smtp_relay = System.get_env("SMTP_RELAY", "email-smtp.ap-southeast-1.amazonaws.com") config :your_app, YourApp.Mailer, adapter: Swoosh.Adapters.SMTP, relay: smtp_relay, username: System.get_env("SMTP_USERNAME"), password: System.get_env("SMTP_PASSWORD"), port: System.get_env("SMTP_PORT", "587") |> String.to_integer(), ssl: false, tls: :always, auth: :always, retries: 3, no_mx_lookups: false, tls_options: [ verify: :verify_peer, middlebox_comp_mode: false, cacerts: :public_key.cacerts_get(), server_name_indication: smtp_relay |> String.to_charlist(), depth: 3, log_level: :warning ]