stefannovak

Stuck setting up SMTP, TLS issues

Hi,

Likely a noob issue, apologies! I’ve been trying to migrate from a simple SendGrid Swoosh adaptor to an SMTP one, as I’ve switched over to Zoho mail. I can’t get an email to fire, but I can get it to work using a simple Python script, so I know the account setup and auth stuff is fine, I just can’t get Phoenix working with me. I’m deep in the rabbit hole of trying things I’m finding through AI or this forum and GitHub, without knowing what I’m really doing (never configured SMTP before)

I continue to get the following error, I’m using the register account email generated by phx auth.

{:error, {:retries_exceeded, {:temporary_failure, ~c"185.230.214.164", :tls_failed}}}

I’ve got this in my dev.exs

config :swoosh, :api_client, false

config :embernotes, Embernotes.Mailer,
  adapter: Swoosh.Adapters.SMTP,
  relay: "smtp.zoho.eu",
  username: "username",
  password: "password",
  port: 587,
  ssl: false,
  tls: :always,
  auth: :always,
  tls_options: [
    verify: :verify_peer,
    versions: ["tlsv1.3"],
    cacerts: :public_key.cacerts_get(),
    depth: 99
  ]

Those tls options are things I’ve found online. Even without them I get the same issue. I hope releasing to Prod isn’t much more difficult than getting this done on dev

From the Zoho docs

SMTP Configuration settings for Zoho Mail - TLS
Outgoing Server Settings: (Personal users with an email address as username@zohomail.com and and Free Organization users):

Outgoing Server Name: smtp.zoho.eu
Port: 587
Security Type: TLS 

Require Authentication: Yes. The email address should match the email address/ email aliases of the account, for which the authentication details are provided.

Any help or direction is appreciated. Thanks!

20 comments

/phoenix #email #smtp #swoosh #tls

0 660 20

2025-09-26 08:44:01 UTC

Marked As Solved

ruslandoga

I wonder if you could try Mua adapter, in the very least it would show the actual error message: Swoosh.Adapters.Mua — Swoosh v1.26.2 (note the extra deps)

config :embernotes, Embernotes.Mailer,
  adapter: Swoosh.Adapters.Mua
  relay: "smtp.zoho.eu",
  auth: [username: "username", password: "password"],
  port: 587

Post #6

Also Liked

tomkonidas

I remember it was a pain for me as well at one point, but I got it to work in one of my projects with the following config:

  config :my_app, MyApp.Mailer,
    adapter: Swoosh.Adapters.SMTP,
    relay: System.fetch_env!("SMTP_SERVER"),
    username: System.fetch_env!("SMTP_USERNAME"),
    password: System.fetch_env!("SMTP_PASSWORD"),
    ssl: false,
    tls: :always,
    tls_options: [verify: :verify_none],
    auth: :always,
    port: System.fetch_env!("SMTP_PORT"),
    retries: 2,
    no_mx_lookups: false

Post #16

LostKobrakai

https://github.com/gen-smtp/gen_smtp/issues/298#issuecomment-1405328435

The options don‘t do well separating starttls from fully tls connections.

Post #2

LostKobrakai

Yeah, providers do just as badly in differenciating it seems.

Post #4

Last Post!

SyahmiRafsan

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
    ]

Post #20