diff --git a/frappe/app.py b/frappe/app.py
index 83efb7de34..ea346a0417 100644
--- a/frappe/app.py
+++ b/frappe/app.py
@@ -143,7 +143,7 @@ def handle_exception(e):
 	http_status_code = getattr(e, "http_status_code", 500)
 	return_as_message = False
 
-	if frappe.local.is_ajax or 'application/json' in frappe.get_request_header('Accept'):
+	if frappe.get_request_header('Accept') and (frappe.local.is_ajax or 'application/json' in frappe.get_request_header('Accept')):
 		# handle ajax responses first
 		# if the request is ajax, send back the trace or error message
 		response = frappe.utils.response.report_error(http_status_code)