diff --git a/landline.gemspec b/landline.gemspec
index 4338025..68e0311 100644
--- a/landline.gemspec
+++ b/landline.gemspec
@@ -16,4 +16,6 @@ Gem::Specification.new do |spec|
   spec.files                 = Dir["lib/**/*"]
   spec.extra_rdoc_files      = Dir["*.md"]
   spec.required_ruby_version = ">= 3.0.0"
+
+  spec.add_dependency 'base64', '~> 0.3.0'
 end
diff --git a/lib/landline/server.rb b/lib/landline/server.rb
index 4f6207e..89c8c43 100644
--- a/lib/landline/server.rb
+++ b/lib/landline/server.rb
@@ -80,7 +80,6 @@ module Landline
         "handle.default" => proc do |code, backtrace: nil, **_extra|
           page = Landline::Util.default_error_page(code, backtrace)
           headers = {
-            "content-length": page.bytesize,
             "content-type": "text/html",
             "x-cascade": true
           }