diff --git a/frappe/utils/response.py b/frappe/utils/response.py
index 60574f5331..fddd478bd4 100644
--- a/frappe/utils/response.py
+++ b/frappe/utils/response.py
@@ -162,7 +162,7 @@ def send_private_file(path):
 	if frappe.local.request.headers.get('X-Use-X-Accel-Redirect'):
 		path = '/protected/' + path
 		response = Response()
-		response.headers[b'X-Accel-Redirect'] = frappe.utils.encode(path)
+		response.headers['X-Accel-Redirect'] = frappe.utils.encode(path)
 
 	else:
 		filepath = frappe.utils.get_site_path(path)