title: Rails ActionMailer adds carriage return (=0D) to end of every line in html
body: <p>My ActionMailer adds a carrige return to the end of every line:</p>
  
  <pre><code>&lt;!DOCTYPE html&gt;=0D
  &lt;html&gt;=0D
  &lt;head&gt;=0D
  ...
  this is stuff=0D
  =0D
  This intro has some content in it.=0D
  =0D
  blah.=0D
  =0D
  </code></pre>
  
  <p>My mail is rendered perfectly fine in the <a href="https://guides.rubyonrails.org/action_mailer_basics.html#previewing-emails" rel="nofollow noreferrer">preview</a> <code>host/rails/mailers/user_mailer/periodic_digest.html</code> (and also in <a href="https://mailcatcher.me/" rel="nofollow noreferrer">mailcatcher</a>), but when I send the mail through Mailgun I end up getting double line spacing between my text.</p>
  
  <p>In <code>app/mailers/user_mailer.rb:periodic_digest</code></p>
  
  <pre><code>m = mail(from: 'blah', to: 'me')
  puts m.html_part.body.decoded
  </code></pre>
  
  <p>I do get correctly formatted html.</p>
  
  <p>How can I send out my html without the carriage return character <code>=0D</code> being appended to every line?</p>