diff --git a/app/models/concerns/fluentd/setting/plugin_parameter.rb b/app/models/concerns/fluentd/setting/plugin_parameter.rb
index 5b85e1a..83ee1d2 100644
--- a/app/models/concerns/fluentd/setting/plugin_parameter.rb
+++ b/app/models/concerns/fluentd/setting/plugin_parameter.rb
@@ -162,7 +162,11 @@ class Fluentd
                       else
                         type
                       end
-          Fluent::Config::REFORMAT_VALUE.call(type_name, value.dup)
+          begin
+            Fluent::Config::REFORMAT_VALUE.call(type_name, value.dup)
+          rescue TypeError
+            Fluent::Config::REFORMAT_VALUE.call(type_name, value)
+          end
         end
       end
     end
diff --git a/config/initializers/dig.rb b/config/initializers/dig.rb
new file mode 100644
index 0000000..084f8e8
--- /dev/null
+++ b/config/initializers/dig.rb
@@ -0,0 +1,8 @@
+unless {}.respond_to?(:dig)
+  begin
+    # backport_dig is faster than dig_rb so prefer backport_dig.
+    require 'backport_dig'
+  rescue LoadError
+    require 'dig_rb'
+  end
+end
diff --git a/fluentd-ui.gemspec b/fluentd-ui.gemspec
index dec9b76..5c5cb74 100644
--- a/fluentd-ui.gemspec
+++ b/fluentd-ui.gemspec
@@ -35,6 +35,7 @@ Gem::Specification.new do |spec|
 
   spec.add_dependency "fluentd", [">= 1.0.0", "< 2"]
   spec.add_dependency 'rails', '~> 5.2.0'
+  spec.add_dependency "dig_rb", "~> 1.0.0"
   spec.add_dependency "bootsnap", ">= 1.1.0"
   spec.add_dependency 'sucker_punch', "~> 2.0.4"
   spec.add_dependency 'addressable'
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index a077ff5..f1dfb09 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -24,6 +24,7 @@ Capybara.javascript_driver = :selenium
 require 'capybara-screenshot/rspec'
 
 require "fluent/load"
+require "fluent/plugin/buf_file"
 
 # Requires supporting ruby files with custom matchers and macros, etc,
 # in spec/support/ and its subdirectories.