diff --git a/erpnext/accounts/doctype/payment_entry/payment_entry.py b/erpnext/accounts/doctype/payment_entry/payment_entry.py
index f29be181e7bf..957403bf895e 100644
--- a/erpnext/accounts/doctype/payment_entry/payment_entry.py
+++ b/erpnext/accounts/doctype/payment_entry/payment_entry.py
@@ -441,7 +441,7 @@ def validate_paid_invoices(self):
 				_(
 					"References {0} of type {1} had no outstanding amount left before submitting the Payment Entry. Now they have a negative outstanding amount."
 				).format(
-					frappe.bold(comma_and((d.reference_name for d in references))),
+					frappe.bold(comma_and([d.reference_name for d in references])),
 					_(reference_doctype),
 				)
 				+ "<br><br>"