Email sending failed, final error: end of file reached

Installation
1

Mail Sending Failed, Final Error: Error - end of file reached

Installation

Refer to this article for installation instructions.
I had a 1p instance first and then installed the forum, but I freed up ports 80/443 in advance.

Error

The email information displayed in the admin backend is:

Email Information
Email Information782×610 26.7 KB

Popup when sending failed:
(Cannot provide, I can only upload one image, but the content of the error popup is Error - end of file reached)

Additional Information

I used a 163 mailbox with SMTP directly. Many people suggest using an email address with my own domain, but we are a bit poor.
I remember that the 587 TLS of NetEase mailbox had some issues* (the original system used 465 for sending mail, I think there’s some reason for that)*.
I modified some parts of the configuration file by searching for information and using AI, mainly these parts:

DISCOURSE_SMTP_ENABLE_SSL: true
DISCOURSE_SMTP_ENABLE_START_TLS: false
DISCOURSE_SMTP_AUTHENTICATION_TYPE: login

app.yml Configuration

## this is the all-in-one, standalone Discourse Docker container template
##
## After making changes to this file, you MUST rebuild
## /var/discourse/launcher rebuild app
##
## BE *VERY* CAREFUL WHEN EDITING!
## YAML FILES ARE SUPER SUPER SENSITIVE TO MISTAKES IN WHITESPACE OR ALIGNMENT!
## visit http://www.yamllint.com/ to validate this file as needed

templates:
  - "templates/postgres.template.yml"
  - "templates/redis.template.yml"
  - "templates/web.template.yml"
  ## Uncomment the next line to enable the IPv6 listener
  #- "templates/web.ipv6.template.yml"
  - "templates/web.ratelimited.template.yml"
  ## Uncomment these two lines if you wish to add Lets Encrypt (https)
  - "templates/web.ssl.template.yml"
  - "templates/web.letsencrypt.ssl.template.yml"

## which TCP/IP ports should this container expose?
## If you want Discourse to share a port with another webserver like Apache or nginx,
## see https://meta.discourse.org/t/17247 for details
expose:
  - "80:80"   # http
  - "443:443" # https

params:
  db_default_text_search_config: "pg_catalog.english"

  ## Set db_shared_buffers to a max of 25% of the total memory.
  ## will be set automatically by bootstrap based on detected RAM, or you can override
  db_shared_buffers: "2048MB"

  ## can improve sorting performance, but adds memory usage per-connection
  #db_work_mem: "40MB"

  ## Which Git revision should this container use? (default: tests-passed)
  #version: tests-passed

env:
  LC_ALL: en_US.UTF-8
  LANG: en_US.UTF-8
  LANGUAGE: en_US.UTF-8
  # DISCOURSE_DEFAULT_LOCALE: en

  ## How many concurrent web requests are supported? Depends on memory and CPU cores.
  ## will be set automatically by bootstrap based on detected CPUs, or you can override
  UNICORN_WORKERS: 8

  ## TODO: The domain name this Discourse instance will respond to
  ## Required. Discourse will not work with a bare IP number.
  DISCOURSE_HOSTNAME: bbs.furina.chat

  ## Uncomment if you want the container to be started with the same
  ## hostname (-h option) as specified above (default "$hostname-$config")
  #DOCKER_USE_HOSTNAME: true

  ## TODO: List of comma delimited emails that will be made admin and developer
  ## on initial signup example 'user1@example.com,user2@example.com'
  DISCOURSE_DEVELOPER_EMAILS: 'images8023@163.com'

  ## TODO: The SMTP mail server used to validate new accounts and send notifications
  # SMTP ADDRESS, username, and password are required
  # WARNING the char '#' in SMTP password can cause problems!
  DISCOURSE_SMTP_ADDRESS: smtp.163.com
  DISCOURSE_SMTP_PORT: 465
  DISCOURSE_SMTP_USER_NAME: phantasm_ai@163.com
  DISCOURSE_SMTP_PASSWORD: "(security token)"
  DISCOURSE_SMTP_ENABLE_SSL: true
  DISCOURSE_SMTP_ENABLE_START_TLS: false           # (optional, default true)
  DISCOURSE_SMTP_DOMAIN: 163.com # (required by some providers)
  DISCOURSE_NOTIFICATION_EMAIL: phantasm_ai@163.com
  DISCOURSE_SMTP_AUTHENTICATION_TYPE: login

  ## If you added the Lets Encrypt template, uncomment below to get a free SSL certificate
  LETSENCRYPT_ACCOUNT_EMAIL: images8023@163.com

  ## The http or https CDN address for this Discourse instance (configured to pull)
  ## see https://meta.discourse.org/t/14857 for details
  #DISCOURSE_CDN_URL: https://discourse-cdn.example.com

  ## The maxmind geolocation IP account ID and license key for IP address lookups
  ## see https://meta.discourse.org/t/-/173941 for details
  #DISCOURSE_MAXMIND_ACCOUNT_ID: 123456
  #DISCOURSE_MAXMIND_LICENSE_KEY: 1234567890123456

## The Docker container is stateless; all data is stored in /shared
volumes:
  - volume:
      host: /var/discourse/shared/standalone
      guest: /shared
  - volume:
      host: /var/discourse/shared/standalone/log/var-log
      guest: /var/log

## Plugins go here
## see https://meta.discourse.org/t/19157 for details
hooks:
  after_code:
    - exec:
        cd: $home/plugins
        cmd:
          - git clone https://github.com/discourse/docker_manager.git
          - git clone https://github.com/discourse/discourse-solved
          - git clone https://github.com/discourse/discourse-reactions

## Any custom commands to run after building
run:
  - exec: echo "Beginning of custom commands"
  ## If you want to set the 'From' email address for your first registration, uncomment and change:
  ## After getting the first signup email, re-comment the line. It only needs to run once.
  #- exec: rails r "SiteSetting.notification_email='info@unconfigured.discourse.org'"
  - exec: echo "End of custom commands"
2

Suggest changing your email. Lark International has a free quota of 15,000 emails per month. Check out my post. If you have any questions, feel free to discuss them here.

https://starorigin.net/t/topic/218