ruby on rails - undefined method `to_model' for #<ActionMailer::MessageDelivery:0xa6e7980> -

i developing web app send bulk email using ror , sendgrid. getting nomethoderror undefined method `to_model' #actionmailer::messagedelivery:0xa6e7980 did mean? to_yaml.

the emails sent , delivered error shows up. being new rails , ruby i'm lost , can't seem figure out remove error after digging internet 6 hours. code follows:
1. test_mailer.rb

class testmailer < applicationmailer     include sendgrid     sendgrid_enable   :ganalytics, :opentrack     default from: 'abc@company.com'      def send_email(e_arr, s_arr)         @e_arr = e_arr         @s_arr = s_arr         headers['x-smtpapi'] = { :to => @e_arr }.to_json         mail(             :to => "this.is@ignored.com",             :subject => "hello user",         ).deliver     end end 

2. routes.rb

    rails.application.routes.draw         root 'static_pages#home'          'static_pages/home'         post 'static_pages/home', to: 'static_pages#func'     end 

3.static_pages_controller.rb

    class staticpagescontroller < applicationcontroller       skip_before_action :verify_authenticity_token       def home        end       def func           postvar = params[:emails];           lines = postvar.split("\n");           arr = [];           lines.each {|line|               arr.push(line.split("@")[0]);           }           redirect_to testmailer.send_email(lines, arr)       end     end 

4. environment.rb

# load rails application. require_relative 'application'  # initialize rails application. rails.application.initialize!  actionmailer::base.smtp_settings = {   :address => "smtp.sendgrid.net",   :port => 25,   :domain => "abc.com",   :authentication => :plain,   :user_name => "xyz",   :password => "pqr" } 

screenshot of error

you can't redirect_to mailer send_mail function.

instead of

redirect_to testmailer.send_email(lines, arr) 

just do

testmailer.send_email(lines, arr).deliver_now 

in separate line redirect_to path want go after sending mail, or render view want, or if func method call existing action, don't anything, , return action.