diff --git a/erpnext/accounts/doctype/sales_invoice/sales_invoice.py b/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
index e6f80ab406677a3d1aa7a48be0eaf4d8f15418c3..3850c877d2823812e46931a491bb7bde3b83be7d 100644
--- a/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
+++ b/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
@@ -275,7 +275,7 @@ class SalesInvoice(SellingController):
 		self.validate_auto_set_posting_time()
 		self.validate_posting_datetime_chronology()
 
-		if not self.is_pos:
+		if not (self.is_pos or self.is_debit_note):
 			self.so_dn_required()
 
 		if cint(self.is_down_payment_invoice) and len([x.sales_order for x in self.get("items")]) > 1:
diff --git a/erpnext/controllers/selling_controller.py b/erpnext/controllers/selling_controller.py
index 4484f608620e2c327308acdc210182d4fda252b1..3705b0728e4d4488e32a4a1b9aada2fed5afcb26 100644
--- a/erpnext/controllers/selling_controller.py
+++ b/erpnext/controllers/selling_controller.py
@@ -28,7 +28,8 @@ class SellingController(StockController):
 	def validate(self):
 		super(SellingController, self).validate()
 		self.validate_items()
-		self.validate_max_discount()
+		if not self.get("is_debit_note"):
+			self.validate_max_discount()
 		self.validate_selling_price()
 		self.set_qty_as_per_stock_uom()
 		self.set_po_nos(for_validate=True)