Can't send mail on 16.04 - DigitalOcean

Tried this tutorial

Got this nasty mess:

Error connecting to Redis on localhost:6379 (Errno::ECONNREFUSED) subscribe fail
ed, reconnecting in 1 second. Call stack ["/var/www/discourse/vendor/bundle/ruby
/2.4.0/gems/redis-4.0.1/lib/redis/client.rb:344:in `rescue in establish_connecti
on'", "/var/www/discourse/vendor/bundle/ruby/2.4.0/gems/redis-4.0.1/lib/redis/cl
ient.rb:328:in `establish_connection'", "/var/www/discourse/vendor/bundle/ruby/2
.4.0/gems/redis-4.0.1/lib/redis/client.rb:99:in `block in connect'", "/var/www/d
iscourse/vendor/bundle/ruby/2.4.0/gems/redis-4.0.1/lib/redis/client.rb:291:in `w
ith_reconnect'", "/var/www/discourse/vendor/bundle/ruby/2.4.0/gems/redis-4.0.1/l
ib/redis/client.rb:98:in `connect'", "/var/www/discourse/vendor/bundle/ruby/2.4.
0/gems/redis-4.0.1/lib/redis/client.rb:363:in `ensure_connected'", "/var/www/dis
course/vendor/bundle/ruby/2.4.0/gems/redis-4.0.1/lib/redis/client.rb:219:in `blo
ck in process'", "/var/www/discourse/vendor/bundle/ruby/2.4.0/gems/redis-4.0.1/l
ib/redis/client.rb:304:in `logging'", "/var/www/discourse/vendor/bundle/ruby/2.4
.0/gems/redis-4.0.1/lib/redis/client.rb:218:in `process'", "/var/www/discourse/v
endor/bundle/ruby/2.4.0/gems/redis-4.0.1/lib/redis/client.rb:118:in `call'", "/v
ar/www/discourse/vendor/bundle/ruby/2.4.0/gems/redis-4.0.1/lib/redis.rb:889:in `
block in get'", "/var/www/discourse/vendor/bundle/ruby/2.4.0/gems/redis-4.0.1/li
b/redis.rb:45:in `block in synchronize'", "/usr/local/lib/ruby/2.4.0/monitor.rb:
214:in `mon_synchronize'", "/var/www/discourse/vendor/bundle/ruby/2.4.0/gems/red
is-4.0.1/lib/redis.rb:45:in `synchronize'", "/var/www/discourse/vendor/bundle/ru
by/2.4.0/gems/redis-4.0.1/lib/redis.rb:888:in `get'", "/var/www/discourse/vendor
/bundle/ruby/2.4.0/gems/message_bus-2.1.4/lib/message_bus/backends/redis.rb:285:
in `process_global_backlog'", "/var/www/discourse/vendor/bundle/ruby/2.4.0/gems/
message_bus-2.1.4/lib/message_bus/backends/redis.rb:321:in `block in global_subs
cribe'", "/var/www/discourse/vendor/bundle/ruby/2.4.0/gems/message_bus-2.1.4/lib
/message_bus/backends/redis.rb:334:in `global_subscribe'", "/var/www/discourse/v
endor/bundle/ruby/2.4.0/gems/message_bus-2.1.4/lib/message_bus.rb:530:in `global
_subscribe_thread'", "/var/www/discourse/vendor/bundle/ruby/2.4.0/gems/message_b
us-2.1.4/lib/message_bus.rb:478:in `block in new_subscriber_thread'"]
Job exception: Error connecting to Redis on localhost:6379 (Errno::ECONNREFUSED)

It says “Mail Sent” 4 times at the bottom of my log.
Here is my complete config:
https://hastebin.com/egorawayif.bash
@pfaffman