diff --git a/lib/rucaptcha.rb b/lib/rucaptcha.rb
index dab485b..93cca50 100644
--- a/lib/rucaptcha.rb
+++ b/lib/rucaptcha.rb
@@ -40,7 +40,7 @@ module RuCaptcha
       length = config.length
 
       unless length.in?(3..7)
-        raise Rucaptcha::Errors::Configuration, 'length config error, value must in 3..7'
+        raise RuCaptcha::Errors::Configuration, 'length config error, value must in 3..7'
       end
 
       strikethrough = config.strikethrough ? 1 : 0
diff --git a/lib/rucaptcha/errors/configuration.rb b/lib/rucaptcha/errors/configuration.rb
index 52738e9..5d4fd1f 100644
--- a/lib/rucaptcha/errors/configuration.rb
+++ b/lib/rucaptcha/errors/configuration.rb
@@ -1,4 +1,4 @@
-module Rucaptcha
+module RuCaptcha
   module Errors
     class Configuration < StandardError; end
   end