Mailtrap SMTP setup guide for Nutify

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Mailtrap SMTP setup guide for Nutify

This guide explains how to configure Mailtrap SMTP in Nutify for email notifications, including a workaround for the hidden From Email field.

Context

When using Mailtrap with Nutify, the SMTP connection may work correctly, but Nutify can still fail with a generic:

Configuration Error

In debug logs, the real error may look like this:

msmtp: envelope from address api not accepted by the server
msmtp: server message: 501 5.1.7 Bad sender address syntax
msmtp: could not send mail

The cause is that Nutify may use the SMTP username as the sender address.

For Mailtrap, the SMTP username is usually:

api

But api is not a valid email sender address. Mailtrap requires the sender address to belong to a verified sending domain.

Example valid sender:

hello@example.com

Required Mailtrap values

In Mailtrap, create or use an SMTP/API token for your verified sending domain.

Typical SMTP values:

Field | Value -- | -- SMTP server | live.smtp.mailtrap.io SMTP port | 587 Username | api Password | Your Mailtrap SMTP/API token Encryption | STARTTLS Sender / From Email | An address from your verified domain Recipient / To Email | Any destination address you want to receive alerts on

Important:

Username = api
From Email = hello@example.com

Do not use api as the sender address.

Problem: From Email field may be hidden

In some Nutify versions, the From Email field exists in the HTML but is hidden in the UI for some providers.

If the field is not visible, Nutify may fall back to the SMTP username as sender.

That creates this invalid msmtp configuration:

from           api
user           api

Mailtrap rejects this because api is not a valid sender email address.

The correct configuration should be similar to:

from           hello@example.com
user           api

Workaround: show the hidden From Email field

Open your browser developer tools:

Right click -> Inspect

Look for this field:

<input type="email" id="from_email" name="from_email" placeholder="Sender email address" style="display: none;">

It may be inside a hidden container like:

<div class="options_mail_form_group" style="display: none;">

Temporarily remove the hidden styles.

Change:

<div class="options_mail_form_group" style="display: none;">

to:

<div class="options_mail_form_group">

And change:

<input type="email" id="from_email" name="from_email" placeholder="Sender email address" style="display: none;">

to:

<input type="email" id="from_email" name="from_email" placeholder="Sender email address">

The From Email field should now appear in the Nutify web UI.

Set it to a sender address from your verified Mailtrap domain:

hello@example.com

Then click:

Test Email

If the configuration is correct, Nutify should show:

Test email sent successfully

After that, click:

Save Configuration

Validate saved configuration in SQLite

If Nutify is running in Docker, you can verify that the configuration was saved correctly.

Enter the Nutify container:

docker exec -it nutify sh

Then run:

cd /app/nutify/instance
python3 - <<'PY'

import sqlite3
db = "nutify.db.sqlite"

con = sqlite3.connect(db)

cur = con.cursor()
rows = cur.execute("""

SELECT

id,

smtp_server,

smtp_port,

username,

enabled,

provider,

tls,

tls_starttls,

is_default,

to_email,

from_email,

updated_at

FROM ups_opt_mail_config

ORDER BY id;

""").fetchall()
print("Rows:", len(rows))

for r in rows:

print(r)
con.close()

PY

Expected result:

smtp_server  = live.smtp.mailtrap.io

smtp_port    = 587

username     = api

tls          = 1

tls_starttls = 1

to_email     = your recipient email

from_email   = your verified sender email

The important part is:

from_email = hello@example.com

If from_email is empty, NULL, or api, the configuration is likely still wrong.

Optional: mark the configuration as default

If you only have one email configuration but is_default is set to 0, Nutify may still use it as the first available configuration. However, you can mark it as default manually.

Inside the container:

cd /app/nutify/instance

python3 - <<'PY'

import sqlite3
con = sqlite3.connect("nutify.db.sqlite")

cur = con.cursor()
cur.execute("UPDATE ups_opt_mail_config SET is_default = 1 WHERE id = 1")

con.commit()
print(cur.execute("""

SELECT id, smtp_server, username, enabled, is_default, to_email, from_email

FROM ups_opt_mail_config

""").fetchall())
con.close()

PY

Expected result:

(1, 'live.smtp.mailtrap.io', 'api', 1, 1, 'recipient@example.com', 'hello@example.com')

Direct SMTP test from inside the container

If you want to verify that Mailtrap itself works from the Nutify container, you can run this test.

Enter the container:

docker exec -it nutify sh

Run:

python3 - <<'PY'

import smtplib

import ssl

from email.message import EmailMessage

from getpass import getpass

host = "live.smtp.mailtrap.io"

port = 587

username = "api"
password = getpass("Mailtrap token: ").strip()

from_email = input("From email from verified domain: ").strip()

to_email = input("Recipient email: ").strip()
msg = EmailMessage()

msg["From"] = from_email

msg["To"] = to_email

msg["Subject"] = "Mailtrap SMTP test from Nutify container"

msg.set_content("This is a direct SMTP STARTTLS test from the Nutify container.")
with smtplib.SMTP(host, port, timeout=20) as smtp:

smtp.set_debuglevel(1)

smtp.ehlo()

smtp.starttls(context=ssl.create_default_context())

smtp.ehlo()

smtp.login(username, password)

smtp.send_message(msg)
print("OK: email sent")

PY

A successful SMTP transaction should end with something similar to:

250 2.0.0 Ok: queued

OK: email sent

Security note:

Do not publish or share lines containing:

AUTH PLAIN ...

That line contains your credentials encoded in Base64. If it was shared publicly, rotate the Mailtrap token immediately.

Common errors

501 5.1.7 Bad sender address syntax

Cause:

from = api

Fix:

Use a valid sender address from your verified Mailtrap domain:

from = hello@example.com

From Header Domain Mismatch

Cause:

The sender email does not belong to a verified Mailtrap sending domain.

Fix:

Use an address from your verified domain.

Example:

hello@your-verified-domain.com

Configuration Error with no useful web UI details

Cause:

Nutify may hide the real msmtp error in the UI.

Fix:

Enable debug logging or check the Nutify mail logs. Look for msmtp stderr.

SMTP works manually, but Nutify fails

Cause:

The manual test probably used a valid From: email, while Nutify used api as the envelope sender.

Fix:

Set the hidden from_email field to a valid verified sender address.

Suggested UI improvement

This may be considered a small UI/UX issue.

Nutify already has a from_email field, but it may be hidden for some SMTP providers. For providers like Mailtrap, SendGrid, Mailgun, Amazon SES, Postmark, etc., the sender address can be different from the SMTP username and is often required.

Suggested improvement:

Always show the From Email field for custom SMTP providers.

Or at least show it when:

SMTP username is not a valid email address

Example:

username = api

from_email = hello@example.com

This would avoid the invalid sender error with Mailtrap.