diff --git a/Gemfile b/Gemfile
index 9cc97715..3eb8e897 100644
--- a/Gemfile
+++ b/Gemfile
@@ -27,7 +27,7 @@ gem 'zip-zip'
 gem 'simple_enum'
 gem 'uuidtools'
 #gem 'dav4rack'
-gem 'dav4rack', git: 'https://github.com/planio-gmbh/dav4rack.git', branch: 'master'
+gem 'dav4rack', git: 'https://github.com/picman/dav4rack.git', branch: 'master'
 gem 'dalli'
 unless %w(easyproject easy_gantt).any? { |plugin| Dir.exist?(File.expand_path("../../#{plugin}", __FILE__)) }
   gem 'redmine_extensions', '~> 0.2.5'
diff --git a/lib/redmine_dmsf/webdav/custom_middleware.rb b/lib/redmine_dmsf/webdav/custom_middleware.rb
index b764042c..a225b213 100644
--- a/lib/redmine_dmsf/webdav/custom_middleware.rb
+++ b/lib/redmine_dmsf/webdav/custom_middleware.rb
@@ -44,6 +44,9 @@ module RedmineDmsf
           status, headers, body = @dav_app.call env
         rescue Exception => e
           Rails.logger.error e.message
+          status = e
+          headers = {}
+          body = ['']
         end
         # If the URL map generated by Rack::Builder did not find a matching path,
         # it will return a 404 along with the X-Cascade header set to 'pass'.