Redmine

Hello,

I know there are some other discussions but I can not make it.

Environment:
  Redmine version                3.3.2.stable
  Ruby version                   2.3.0-p0 (2015-12-25) [x86_64-linux]
  Rails version                  4.2.7.1
  Environment                    production
  Database adapter               PostgreSQL
  Ubuntu                         16.04
  Webrick

configuration.yml

default:
  email_delivery:
    delivery_method: :smtp
    smtp_settings:
      enable_starttls_auto: true
      address: "smtp.mailserver.de" 
      port: 587
      domain: "domain" 
      authentication: :login
      user_name: "username" 
      password: "passwort" 

production:
  email_delivery:
    delivery_method: :smtp
    smtp_settings:
      enable_starttls_auto: true
      address: "smtp.mailserver.de" 
      port: 587
      domain: "domain" 
      authentication: :login
      user_name: "username" 
      password: "passwort" 

Error Message:
An error occurred while sending mail (execution expired)

I have already tried the solutions from can't send mail using smtp "An error occurred while sendi... and many other posts.

Is here anyone who can help me with that?

Gems Installed:

Using rake 12.0.0
Using i18n 0.8.0
Using json 1.8.6
Using minitest 5.10.1
Using thread_safe 0.3.5
Using builder 3.2.3
Using erubis 2.7.0
Using mini_portile2 2.1.0
Using rack 1.6.5
Using mime-types-data 3.2016.0521
Using arel 6.0.4
Using public_suffix 2.0.5
Using coderay 1.1.1
Using concurrent-ruby 1.0.4
Using docile 1.1.5
Using htmlentities 4.3.1
Using thor 0.19.4
Using mimemagic 0.3.2
Using multi_json 1.12.1
Using net-ldap 0.12.1
Using pg 0.18.4
Using ruby-openid 2.3.0
Using bundler 1.14.4
Using rbpdf-font 1.19.0
Using redcarpet 3.3.4
Using redmine_crm 0.0.8
Using request_store 1.0.5
Using ruby-ole 1.2.12
Using simplecov-html 0.9.0
Using vcard 0.2.15
Using tzinfo 1.2.2
Using nokogiri 1.7.0.1
Using rack-test 0.6.3
Using mime-types 3.1
Using addressable 2.5.0
Using sprockets 3.7.1
Using rack-openid 1.4.2
Using rbpdf 1.19.0
Using spreadsheet 0.6.9
Using simplecov 0.9.2
Using activesupport 4.2.7.1
Using loofah 2.0.3
Using mail 2.6.4
Using css_parser 1.4.8
Using simplecov-rcov 0.2.3
Using rails-deprecated_sanitizer 1.0.3
Using globalid 0.3.7
Using activemodel 4.2.7.1
Using rails-html-sanitizer 1.0.3
Using roadie 3.2.1
Using rails-dom-testing 1.0.8
Using activejob 4.2.7.1
Using activerecord 4.2.7.1
Using protected_attributes 1.1.3
Using actionview 4.2.7.1
Using actionpack 4.2.7.1
Using actionmailer 4.2.7.1
Using actionpack-action_caching 1.2.0
Using actionpack-xml_parser 1.0.2
Using railties 4.2.7.1
Using sprockets-rails 3.2.0
Using jquery-rails 3.1.4
Using roadie-rails 1.1.1
Using rails 4.2.7.1

Thank you in advance.
Regards
Torben