diff --git a/modules/openapi-generator/src/main/resources/ruby-client/configuration.mustache b/modules/openapi-generator/src/main/resources/ruby-client/configuration.mustache
index 0745df86f71..64bf69b157d 100644
--- a/modules/openapi-generator/src/main/resources/ruby-client/configuration.mustache
+++ b/modules/openapi-generator/src/main/resources/ruby-client/configuration.mustache
@@ -171,7 +171,7 @@ module {{moduleName}}
 
     # Returns base URL for specified operation based on server settings
     def base_url(operation = nil)
-      index = server_operation_index.fetch(operation, server_index)
+      index = server_operation_index[operation]
       return "#{scheme}://#{[host, base_path].join('/').gsub(/\/+/, '/')}".sub(/\/+\z/, '') if index == nil
 
       server_url(index, server_operation_variables.fetch(operation, server_variables), operation_server_settings[operation])
diff --git a/samples/client/petstore/ruby-autoload/lib/petstore/configuration.rb b/samples/client/petstore/ruby-autoload/lib/petstore/configuration.rb
index 962ae306fed..651af46011c 100644
--- a/samples/client/petstore/ruby-autoload/lib/petstore/configuration.rb
+++ b/samples/client/petstore/ruby-autoload/lib/petstore/configuration.rb
@@ -200,7 +200,7 @@ module Petstore
 
     # Returns base URL for specified operation based on server settings
     def base_url(operation = nil)
-      index = server_operation_index.fetch(operation, server_index)
+      index = server_operation_index[operation]
       return "#{scheme}://#{[host, base_path].join('/').gsub(/\/+/, '/')}".sub(/\/+\z/, '') if index == nil
 
       server_url(index, server_operation_variables.fetch(operation, server_variables), operation_server_settings[operation])
diff --git a/samples/client/petstore/ruby-faraday/lib/petstore/configuration.rb b/samples/client/petstore/ruby-faraday/lib/petstore/configuration.rb
index 401e8c2d216..ca52e5afe25 100644
--- a/samples/client/petstore/ruby-faraday/lib/petstore/configuration.rb
+++ b/samples/client/petstore/ruby-faraday/lib/petstore/configuration.rb
@@ -204,7 +204,7 @@ module Petstore
 
     # Returns base URL for specified operation based on server settings
     def base_url(operation = nil)
-      index = server_operation_index.fetch(operation, server_index)
+      index = server_operation_index[operation]
       return "#{scheme}://#{[host, base_path].join('/').gsub(/\/+/, '/')}".sub(/\/+\z/, '') if index == nil
 
       server_url(index, server_operation_variables.fetch(operation, server_variables), operation_server_settings[operation])
diff --git a/samples/client/petstore/ruby/lib/petstore/configuration.rb b/samples/client/petstore/ruby/lib/petstore/configuration.rb
index 962ae306fed..651af46011c 100644
--- a/samples/client/petstore/ruby/lib/petstore/configuration.rb
+++ b/samples/client/petstore/ruby/lib/petstore/configuration.rb
@@ -200,7 +200,7 @@ module Petstore
 
     # Returns base URL for specified operation based on server settings
     def base_url(operation = nil)
-      index = server_operation_index.fetch(operation, server_index)
+      index = server_operation_index[operation]
       return "#{scheme}://#{[host, base_path].join('/').gsub(/\/+/, '/')}".sub(/\/+\z/, '') if index == nil
 
       server_url(index, server_operation_variables.fetch(operation, server_variables), operation_server_settings[operation])
diff --git a/samples/openapi3/client/extensions/x-auth-id-alias/ruby-client/lib/x_auth_id_alias/configuration.rb b/samples/openapi3/client/extensions/x-auth-id-alias/ruby-client/lib/x_auth_id_alias/configuration.rb
index 325c7afb8e8..7413da89399 100644
--- a/samples/openapi3/client/extensions/x-auth-id-alias/ruby-client/lib/x_auth_id_alias/configuration.rb
+++ b/samples/openapi3/client/extensions/x-auth-id-alias/ruby-client/lib/x_auth_id_alias/configuration.rb
@@ -200,7 +200,7 @@ module XAuthIDAlias
 
     # Returns base URL for specified operation based on server settings
     def base_url(operation = nil)
-      index = server_operation_index.fetch(operation, server_index)
+      index = server_operation_index[operation]
       return "#{scheme}://#{[host, base_path].join('/').gsub(/\/+/, '/')}".sub(/\/+\z/, '') if index == nil
 
       server_url(index, server_operation_variables.fetch(operation, server_variables), operation_server_settings[operation])
diff --git a/samples/openapi3/client/features/dynamic-servers/ruby/lib/dynamic_servers/configuration.rb b/samples/openapi3/client/features/dynamic-servers/ruby/lib/dynamic_servers/configuration.rb
index 23c395ce9b4..2d51ef38bc5 100644
--- a/samples/openapi3/client/features/dynamic-servers/ruby/lib/dynamic_servers/configuration.rb
+++ b/samples/openapi3/client/features/dynamic-servers/ruby/lib/dynamic_servers/configuration.rb
@@ -200,7 +200,7 @@ module DynamicServers
 
     # Returns base URL for specified operation based on server settings
     def base_url(operation = nil)
-      index = server_operation_index.fetch(operation, server_index)
+      index = server_operation_index[operation]
       return "#{scheme}://#{[host, base_path].join('/').gsub(/\/+/, '/')}".sub(/\/+\z/, '') if index == nil
 
       server_url(index, server_operation_variables.fetch(operation, server_variables), operation_server_settings[operation])
diff --git a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/configuration.rb b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/configuration.rb
index 78bc5b136be..338900b151f 100644
--- a/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/configuration.rb
+++ b/samples/openapi3/client/features/generate-alias-as-model/ruby-client/lib/petstore/configuration.rb
@@ -200,7 +200,7 @@ module Petstore
 
     # Returns base URL for specified operation based on server settings
     def base_url(operation = nil)
-      index = server_operation_index.fetch(operation, server_index)
+      index = server_operation_index[operation]
       return "#{scheme}://#{[host, base_path].join('/').gsub(/\/+/, '/')}".sub(/\/+\z/, '') if index == nil
 
       server_url(index, server_operation_variables.fetch(operation, server_variables), operation_server_settings[operation])