🐞 Bug: Error trying to send SMTP notification to Mailrise

[torquilcorkerton]

Bug Description

I have just set up Mailrise to use as a notification gateway and although I know Mailrise is working (by successfully testing it with other services that send SMTP to my Mailrise instance), when I enable Email Notifications in Arcane, enter all the details for my Mailrise instance, I get the following error when trying to send a Test or Image Update email:

Steps To Reproduce

1. Enable Email Notifications.
2. Complete the following fields:

SMTP Host: <my_home_server.local>
SMTP Port: 8025
SMTP Username: <mailrise_basic_auth_username>
SMTP Password: <mailrise_basic_auth_password>
From Address: <my_valid_email_address>
To Address: hassio@mailrise.xyz (I'm sending notifications to Home Assistant)
TLS Mode: None

4. Click Simple Test Email or Image Update Email.
5. Receive error quoted above.

Expected Behavior

I have seen the test emails work when inputting settings for my own email's SMTP gateway so I expect the test emails to work successfully when I change the details for my Mailrise instance.

Actual Behavior

Instead, I get this error:

Failed to send test notification: Failed to send test notification: failed to send email:
failed to close data writer: SMTP error 500: Line too long (see RFC5321 4.5.3.1.6)

Screenshots

No response

Arcane Version

v1.10.1

Installation Method

Docker Compose (Recommended)

Environment Type

Local Docker (Single instance)

Database Type

SQLite (Default)

Operating System

Linux

Docker Version

Docker version 29.1.3, build f52814d

Browser & Version

Version 26.2 (21623.1.14.11.9)

Relevant Logs or Error Messages

Dec 24 12:35:03.840 INF Incoming request request.time=2025-12-24T12:35:03.832Z request.method=POST request.host=home-server.academycottage.local:3552 request.path=/api/environments/0/notifications/settings request.query="" request.params=map[id:0] request.route=/api/environments/:id/notifications/settings request.ip=10.0.0.118 request.referer=http://my_server.local:3552/settings/notifications request.length=155 response.time=2025-12-24T12:35:03.840Z response.latency=8.725005ms response.status=200 response.length=57
Dec 24 12:35:03.855 INF Incoming request request.time=2025-12-24T12:35:03.847Z request.method=POST request.host=my_server.local:3552 request.path=/api/environments/0/notifications/settings request.query="" request.params=map[id:0] request.route=/api/environments/:id/notifications/settings request.ip=10.0.0.118 request.referer=http://my_server.local:3552/settings/notifications request.length=308 response.time=2025-12-24T12:35:03.855Z response.latency=8.042864ms response.status=200 response.length=315
Dec 24 12:35:03.870 INF Incoming request request.time=2025-12-24T12:35:03.863Z request.method=POST request.host=my_server.local:3552 request.path=/api/environments/0/notifications/apprise request.query="" request.params=map[id:0] request.route=/api/environments/:id/notifications/apprise request.ip=10.0.0.118 request.referer=http://my_server.local:3552/settings/notifications request.length=80 response.time=2025-12-24T12:35:03.870Z response.latency=7.121157ms response.status=200 response.length=80
Dec 24 12:35:03.923 INF HTTP error: 500 internal server error request.time=2025-12-24T12:35:03.883Z request.method=POST request.host=my_server.local:3552 request.path=/api/environments/0/notifications/test/email request.query="type=simple" request.params="map[id:0 provider:email]" request.route=/api/environments/:id/notifications/test/:provider request.ip=10.0.0.118 request.referer=http://my_server.local:3552/settings/notifications request.length=0 response.time=2025-12-24T12:35:03.923Z response.latency=40.006375ms response.status=500 response.length=150

Docker Compose Configuration

services:
  arcane:
    image: ghcr.io/getarcaneapp/arcane:v1.10.1
    container_name: Arcane
    restart: always
    ports:
      - '3552:3552'
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
      - /opt/arcane/data:/app/data
      - /opt:/app/data/projects
    environment:
      - TZ=$TZ
      - APP_URL=$APP_URL
      - PUID=$PUID
      - PGID=$PGID
      - ENCRYPTION_KEY=$ENCRYPTION_KEY
      - JWT_SECRET=$JWT_SECRET

  # Inforamtion from https://getarcane.app/docs/cli/upgrade
  # Upgrade using the command: docker compose run --rm upgrader
  upgrader:
    image: ghcr.io/getarcaneapp/arcane:latest
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
    entrypoint: ['/app/arcane']
    command: ['upgrade', '--auto']
    profiles:
      - tools

volumes:
  arcane-data:

Environment Configuration (.env file)

TZ=Europe/London
APP_URL=http://my_server.local:3552
PUID=1000
PGID=1000
ENCRYPTION_KEY=my_key
JWT_SECRET=my_secret

Additional Context

No response

[kmendell]

Can you try the latest release v1.11.0 and see if this issue is still present?

[torquilcorkerton]

Can you try the latest release v1.11.0 and see if this issue is still present?

Good evening, Kyle. I've given it a try and my results are:

• Simple Test Email - reports Test Notification sent successfully by email and the notification arrives on my phone via Mailrise and Home Assistant.
• Image Update Email - reports Test Notification sent successfully by email, but I receive no notification.
• Batch Image Updates Email - gives me the same error message as initially reported.

Many thanks for the quick response, however, and Merry Christmas!

[kmendell]

@torquilcorkerton Can you try this image? ghcr.io/getarcaneapp/arcane:email-format