diff --git a/app/models/webhook.rb b/app/models/webhook.rb
index 10d2e383d..1eefb2cb5 100644
--- a/app/models/webhook.rb
+++ b/app/models/webhook.rb
@@ -50,7 +50,7 @@ class Webhook < ApplicationRecord
   end
 
   def renderer
-    @renderer ||= ApplicationController.renderer.new
+    @renderer ||= ApplicationController.renderer.new(script_name: "/#{tenant}", https: !Rails.env.local?)
   end
 
   def for_basecamp?
diff --git a/app/models/webhook/delivery.rb b/app/models/webhook/delivery.rb
index fbd3398b0..e90a8decb 100644
--- a/app/models/webhook/delivery.rb
+++ b/app/models/webhook/delivery.rb
@@ -116,6 +116,8 @@ class Webhook::Delivery < ApplicationRecord
     def content_type
       if webhook.for_campfire?
         "text/html"
+      elsif webhook.for_basecamp?
+        "application/x-www-form-urlencoded"
       else
         "application/json"
       end
@@ -123,7 +125,7 @@ class Webhook::Delivery < ApplicationRecord
 
     def payload
       @payload ||= if webhook.for_basecamp?
-        { line: { content: render_payload(formats: :html) } }.to_json
+        { content: render_payload(formats: :html) }.to_query
       elsif webhook.for_campfire?
         render_payload(formats: :html)
       elsif webhook.for_slack?
diff --git a/test/models/webhook/delivery_test.rb b/test/models/webhook/delivery_test.rb
index 80c7af8af..54530bafb 100644
--- a/test/models/webhook/delivery_test.rb
+++ b/test/models/webhook/delivery_test.rb
@@ -126,9 +126,9 @@ class Webhook::DeliveryTest < ActiveSupport::TestCase
 
     request_stub = stub_request(:post, webhook.url)
       .with do |request|
-        body = JSON.parse(request.body)
-        body.key?("line") && body["line"].key?("content") && body["line"]["content"].present? &&
-        request.headers["Content-Type"] == "application/json"
+        body = CGI.parse(request.body)
+        body.key?("content") && body["content"].first.present? &&
+        request.headers["Content-Type"] == "application/x-www-form-urlencoded"
       end
       .to_return(status: 200)