How to fix '535-5.7.8 Username and Password not accepted. Learn more at' error in Devise mail confirmation?
This is related to ActionMailer configuration rather than Devise.
From the documentation authentication should be set to one of the following
:plain, :login or :cram_md5
The following is an excerpt taken from the relevant section in the documentation linked to above and is the explanation of the available options and what they do, so it all depends on your mail server as to which you wish to use however you can see that SSL is not amongst the available options

:authentication - If your mail server requires authentication, you
need to specify the authentication type here. This is a symbol and one
of :plain (will send the password in the clear), :login (will send
password Base64 encoded) or :cram_md5 (combines a Challenge/Response
mechanism to exchange information and a cryptographic Message Digest 5
algorithm to hash important information)

As requested, a typical gmail configuration would be to use SMTP like so
config.action_mailer.delivery_method = :smtp
config.action_mailer.smtp_settings = {
  address:              'smtp.gmail.com',
  port:                 587,
  domain:               'example.com',
  user_name:            '<username>',
  password:             '<password>',
  authentication:       'plain',
  enable_starttls_auto: true,
  open_timeout:         5,
  read_timeout:         5 }

Taken from the rails action mailer documentation section 5.2
Make sure to replace username x's and password x's with your credentials and NEVER post your credentials anywhere public, I suggest you amend your password on your google account immediately, I have edited your question to hide your password but it is still available to view by those with the correct privileges

I'm a beginner programmer Rails. I'll start with a problem: I'm using Devise to work with users, and I tried to enable mail confirmation. It doesn't work, unfortunately. If possible, please help!
My error:
Net::SMTPAuthenticationError in Devise::ConfirmationsController#create
535-5.7.8 Username and Password not accepted. Learn more at
My config/environments/develorment.rb:
config.action_mailer.perform_deliveries = true
config.action_mailer.raise_delivery_errors = true
config.action_mailer.perform_caching = false
config.action_mailer.default_url_options = { host: 'localhost', port: 3000 }
config.action_mailer.delivery_method = :smtp
config.action_mailer.smtp_settings = {
  address: "smtp.gmail.com",
  port: 587,
  authentication: "plain",
  enable_starttls_auto: true,
  user_name: "xyz@gmail.com",
  password: "xyz", 
  domain: "gmail.com",
  openssl_verify_mode: "none",
}

My config/initializers/devise.rb
config.mailer_sender = "xxx@gmail.com"

config.mailer = 'Devise::Mailer'

My server starts with configurations:
=> Booting Puma
=> Rails 7.0.5 application starting in development
=> Run `bin/rails server --help` for more startup options
Puma starting in single mode...
* Puma version: 5.6.5 (ruby 3.2.0-p0) ("Birdie's Version")
*  Min threads: 5
*  Max threads: 5
*  Environment: development
*          PID: 6074
* Listening on http://127.0.0.1:3000
* Listening on http://[::1]:3000
Use Ctrl-C to stop

And Errors in files (or what is it called):
net-smtp (0.3.3) lib/net/smtp.rb:1088:in `check_auth_response'
net-smtp (0.3.3) lib/net/smtp.rb:845:in `auth_plain'
net-smtp (0.3.3) lib/net/smtp.rb:837:in `public_send'
net-smtp (0.3.3) lib/net/smtp.rb:837:in `authenticate'
net-smtp (0.3.3) lib/net/smtp.rb:670:in `do_start'
net-smtp (0.3.3) lib/net/smtp.rb:611:in `start'
mail (2.8.1) lib/mail/network/delivery_methods/smtp.rb:109:in `start_smtp_session'
mail (2.8.1) lib/mail/network/delivery_methods/smtp.rb:100:in `deliver!'
mail (2.8.1) lib/mail/message.rb:2145:in `do_delivery'
mail (2.8.1) lib/mail/message.rb:253:in `block in deliver'
actionmailer (7.0.5) lib/action_mailer/base.rb:588:in `block in deliver_mail'
activesupport (7.0.5) lib/active_support/notifications.rb:206:in `block in instrument'
activesupport (7.0.5) lib/active_support/notifications/instrumenter.rb:24:in `instrument'
activesupport (7.0.5) lib/active_support/notifications.rb:206:in `instrument'
actionmailer (7.0.5) lib/action_mailer/base.rb:586:in `deliver_mail'
mail (2.8.1) lib/mail/message.rb:253:in `deliver'
actionmailer (7.0.5) lib/action_mailer/message_delivery.rb:119:in `block in deliver_now'
actionmailer (7.0.5) lib/action_mailer/rescuable.rb:17:in `handle_exceptions'
actionmailer (7.0.5) lib/action_mailer/message_delivery.rb:118:in `deliver_now'
devise (4.9.2) lib/devise/models/authenticatable.rb:204:in `send_devise_notification'
devise (4.9.2) lib/devise/models/confirmable.rb:121:in `send_confirmation_instructions'
devise (4.9.2) lib/devise/models/confirmable.rb:136:in `block in resend_confirmation_instructions'
devise (4.9.2) lib/devise/models/confirmable.rb:239:in `pending_any_confirmation'
devise (4.9.2) lib/devise/models/confirmable.rb:135:in `resend_confirmation_instructions'
devise (4.9.2) lib/devise/models/confirmable.rb:321:in `send_confirmation_instructions'
devise (4.9.2) app/controllers/devise/confirmations_controller.rb:11:in `create'
actionpack (7.0.5) lib/action_controller/metal/basic_implicit_render.rb:6:in `send_action'
actionpack (7.0.5) lib/abstract_controller/base.rb:215:in `process_action'
actionpack (7.0.5) lib/action_controller/metal/rendering.rb:165:in `process_action'
actionpack (7.0.5) lib/abstract_controller/callbacks.rb:234:in `block in process_action'
activesupport (7.0.5) lib/active_support/callbacks.rb:118:in `block in run_callbacks'
actiontext (7.0.5) lib/action_text/rendering.rb:20:in `with_renderer'
actiontext (7.0.5) lib/action_text/engine.rb:69:in `block (4 levels) in <class:Engine>'
activesupport (7.0.5) lib/active_support/callbacks.rb:127:in `instance_exec'
activesupport (7.0.5) lib/active_support/callbacks.rb:127:in `block in run_callbacks'
activesupport (7.0.5) lib/active_support/callbacks.rb:138:in `run_callbacks'
actionpack (7.0.5) lib/abstract_controller/callbacks.rb:233:in `process_action'
actionpack (7.0.5) lib/action_controller/metal/rescue.rb:22:in `process_action'
actionpack (7.0.5) lib/action_controller/metal/instrumentation.rb:67:in `block in process_action'
activesupport (7.0.5) lib/active_support/notifications.rb:206:in `block in instrument'
activesupport (7.0.5) lib/active_support/notifications/instrumenter.rb:24:in `instrument'
activesupport (7.0.5) lib/active_support/notifications.rb:206:in `instrument'
actionpack (7.0.5) lib/action_controller/metal/instrumentation.rb:66:in `process_action'
actionpack (7.0.5) lib/action_controller/metal/params_wrapper.rb:259:in `process_action'
activerecord (7.0.5) lib/active_record/railties/controller_runtime.rb:27:in `process_action'
actionpack (7.0.5) lib/abstract_controller/base.rb:151:in `process'
actionview (7.0.5) lib/action_view/rendering.rb:39:in `process'
actionpack (7.0.5) lib/action_controller/metal.rb:188:in `dispatch'
actionpack (7.0.5) lib/action_controller/metal.rb:251:in `dispatch'
actionpack (7.0.5) lib/action_dispatch/routing/route_set.rb:49:in `dispatch'
actionpack (7.0.5) lib/action_dispatch/routing/route_set.rb:32:in `serve'
actionpack (7.0.5) lib/action_dispatch/routing/mapper.rb:18:in `block in <class:Constraints>'
actionpack (7.0.5) lib/action_dispatch/routing/mapper.rb:48:in `serve'
actionpack (7.0.5) lib/action_dispatch/journey/router.rb:50:in `block in serve'
actionpack (7.0.5) lib/action_dispatch/journey/router.rb:32:in `each'
actionpack (7.0.5) lib/action_dispatch/journey/router.rb:32:in `serve'
actionpack (7.0.5) lib/action_dispatch/routing/route_set.rb:852:in `call'
warden (1.2.9) lib/warden/manager.rb:36:in `block in call'
warden (1.2.9) lib/warden/manager.rb:34:in `catch'
warden (1.2.9) lib/warden/manager.rb:34:in `call'
rack (2.2.7) lib/rack/tempfile_reaper.rb:15:in `call'
rack (2.2.7) lib/rack/etag.rb:27:in `call'
rack (2.2.7) lib/rack/conditional_get.rb:40:in `call'
rack (2.2.7) lib/rack/head.rb:12:in `call'
actionpack (7.0.5) lib/action_dispatch/http/permissions_policy.rb:38:in `call'
actionpack (7.0.5) lib/action_dispatch/http/content_security_policy.rb:36:in `call'
rack (2.2.7) lib/rack/session/abstract/id.rb:266:in `context'
rack (2.2.7) lib/rack/session/abstract/id.rb:260:in `call'
actionpack (7.0.5) lib/action_dispatch/middleware/cookies.rb:704:in `call'
activerecord (7.0.5) lib/active_record/migration.rb:603:in `call'
actionpack (7.0.5) lib/action_dispatch/middleware/callbacks.rb:27:in `block in call'
activesupport (7.0.5) lib/active_support/callbacks.rb:99:in `run_callbacks'
actionpack (7.0.5) lib/action_dispatch/middleware/callbacks.rb:26:in `call'
actionpack (7.0.5) lib/action_dispatch/middleware/executor.rb:14:in `call'
actionpack (7.0.5) lib/action_dispatch/middleware/actionable_exceptions.rb:17:in `call'
actionpack (7.0.5) lib/action_dispatch/middleware/debug_exceptions.rb:28:in `call'
web-console (4.2.0) lib/web_console/middleware.rb:132:in `call_app'
web-console (4.2.0) lib/web_console/middleware.rb:28:in `block in call'
web-console (4.2.0) lib/web_console/middleware.rb:17:in `catch'
web-console (4.2.0) lib/web_console/middleware.rb:17:in `call'
actionpack (7.0.5) lib/action_dispatch/middleware/show_exceptions.rb:26:in `call'
railties (7.0.5) lib/rails/rack/logger.rb:40:in `call_app'
railties (7.0.5) lib/rails/rack/logger.rb:25:in `block in call'
activesupport (7.0.5) lib/active_support/tagged_logging.rb:99:in `block in tagged'
activesupport (7.0.5) lib/active_support/tagged_logging.rb:37:in `tagged'
activesupport (7.0.5) lib/active_support/tagged_logging.rb:99:in `tagged'
railties (7.0.5) lib/rails/rack/logger.rb:25:in `call'
sprockets-rails (3.4.2) lib/sprockets/rails/quiet_assets.rb:13:in `call'
actionpack (7.0.5) lib/action_dispatch/middleware/remote_ip.rb:93:in `call'
actionpack (7.0.5) lib/action_dispatch/middleware/request_id.rb:26:in `call'
rack (2.2.7) lib/rack/method_override.rb:24:in `call'
rack (2.2.7) lib/rack/runtime.rb:22:in `call'
activesupport (7.0.5) lib/active_support/cache/strategy/local_cache_middleware.rb:29:in `call'
actionpack (7.0.5) lib/action_dispatch/middleware/server_timing.rb:61:in `block in call'
actionpack (7.0.5) lib/action_dispatch/middleware/server_timing.rb:26:in `collect_events'
actionpack (7.0.5) lib/action_dispatch/middleware/server_timing.rb:60:in `call'
actionpack (7.0.5) lib/action_dispatch/middleware/executor.rb:14:in `call'
actionpack (7.0.5) lib/action_dispatch/middleware/static.rb:23:in `call'
rack (2.2.7) lib/rack/sendfile.rb:110:in `call'
actionpack (7.0.5) lib/action_dispatch/middleware/host_authorization.rb:137:in `call'
railties (7.0.5) lib/rails/engine.rb:530:in `call'
puma (5.6.5) lib/puma/configuration.rb:252:in `call'
puma (5.6.5) lib/puma/request.rb:77:in `block in handle_request'
puma (5.6.5) lib/puma/thread_pool.rb:340:in `with_force_shutdown'
puma (5.6.5) lib/puma/request.rb:76:in `handle_request'
puma (5.6.5) lib/puma/server.rb:443:in `process_client'
puma (5.6.5) lib/puma/thread_pool.rb:147:in `block in spawn_thread'

The message is shown in the terminal.
And yes, I know it's important, e-mail exists, and the data is taken from it.
I tried many options, including the part of the code that I ended up with. Nothing helps.
