diff --git a/src/server/internalServer.cpp b/src/server/internalServer.cpp
index bc14851f9..f94a82990 100644
--- a/src/server/internalServer.cpp
+++ b/src/server/internalServer.cpp
@@ -877,7 +877,9 @@ std::unique_ptr<Response> InternalServer::handle_raw(const RequestContext& reque
 
   if (archive == nullptr) {
     const std::string error_details = "No such book: " + bookName;
-    return Response::build_404(*this, request.get_full_url(), error_details);
+    return HTTP404HtmlResponse(*this, request)
+           + urlNotFoundMsg
+           + error_details;
   }
 
   // Remove the beggining of the path:
diff --git a/src/server/response.cpp b/src/server/response.cpp
index f07a1e6d2..da6fe00b7 100644
--- a/src/server/response.cpp
+++ b/src/server/response.cpp
@@ -127,8 +127,12 @@ HTTP404HtmlResponse& HTTP404HtmlResponse::operator+(UrlNotFoundMsg /*unused*/)
 {
   const std::string requestUrl = m_request.get_full_url();
   kainjow::mustache::mustache msgTmpl(R"(The requested URL "{{url}}" was not found on this server.)");
-  const auto urlNotFoundMsgText = msgTmpl.render({"url", requestUrl});
-  m_data["details"].push_back({"p", urlNotFoundMsgText});
+  return *this + msgTmpl.render({"url", requestUrl});
+}
+
+HTTP404HtmlResponse& HTTP404HtmlResponse::operator+(const std::string& msg)
+{
+  m_data["details"].push_back({"p", msg});
   return *this;
 }
 
diff --git a/src/server/response.h b/src/server/response.h
index 7826d3e72..ee45e1d3f 100644
--- a/src/server/response.h
+++ b/src/server/response.h
@@ -185,6 +185,7 @@ struct HTTP404HtmlResponse : ContentResponseBlueprint
                       const RequestContext& request);
 
   HTTP404HtmlResponse& operator+(UrlNotFoundMsg /*unused*/);
+  HTTP404HtmlResponse& operator+(const std::string& errorDetails);
 };
 
 class ItemResponse : public Response {