sensu mailer handler using mail gem ruby

i am facing some issue using sensu mailer handler, please help me out to solve this issue

i think i am facing port issue, does anyone have any idea.

"output":["/opt/sensu/embedded/lib/ruby/2.3.0/net/smtp.rb:542:in initialize': execution expired (Net::OpenTimeout)\n\tfrom /opt/sensu/embedded/lib/ruby/2.3.0/net/smtp.rb:542:inopen'\n\tfrom /opt/sensu/embedded/lib/ruby/2.3.0/net/smtp.rb:542:in tcp_socket'\n\tfrom /opt/sensu/embedded/lib/ruby/2.3.0/net/smtp.rb:552:inblock in do_start'\n\tfrom /opt/sensu/embedded/lib/ruby/2.3.0/timeout.rb:101:in timeout'\n\tfrom /opt/sensu/embedded/lib/ruby/2.3.0/net/smtp.rb:551:indo_start'\n\tfrom /opt/sensu/embedded/lib/ruby/2.3.0/net/smtp.rb:521:in start'\n\tfrom /opt/sensu/embedded/lib/ruby/gems/2.3.0/gems/mail-2.6.4/lib/mail/network/delivery_methods/smtp.rb:113:indeliver!'\n\tfrom /opt/sensu/embedded/lib/ruby/gems/2.3.0/gems/mail-2.6.4/lib/mail/message.rb:2149:in do_delivery'\n\tfrom /opt/sensu/embedded/lib/ruby/gems/2.3.0/gems/mail-2.6.4/lib/mail/message.rb:239:indeliver'\n\tfrom /opt/sensu/embedded/lib/ruby/gems/2.3.0/gems/mail-2.6.4/lib/mail/mail.rb:141:in deliver'\n\tfrom /etc/sensu/handlers/handler-mailer.rb:233:inrescue in handle'\n\tfrom /etc/sensu/handlers/handler-mailer.rb:218:in handle'\n\tfrom /opt/sensu/embedded/lib/ruby/gems/2.3.0/gems/sensu-plugin-1.3.0/lib/sensu-handler.rb:57:inblock in '\n"]

Finally found the issue, firewall is blocking port 587.