Corrected with rubocop cop 'Lint/UnreachableCode'.

.rubocop.yml

@@ -208,7 +208,5 @@ Style/SpaceBeforeComment:
   Enabled: false
 Lint/UselessAssignment:
   Enabled: false
-Lint/UnreachableCode:
-  Enabled: false
 Lint/ShadowingOuterLocalVariable:
   Enabled: false

app/controllers/import_otrs_controller.rb

@@ -104,7 +104,6 @@ class ImportOtrsController < ApplicationController
   private
 
   def setup_done
-    return false
     count = User.all.count()
     done = true
     if count <= 2

lib/rss.rb

@@ -10,7 +10,6 @@ module Rss
       response = UserAgent.request(url)
       if !response.success?
         fail "Can't fetch '#{url}', http code: #{response.code}"
-        return
       end
       rss     = SimpleRSS.parse response.body
       items   = []