Merge pull request #40634 from wojosc/patch-42

refactor: better pop up message for Internal Customer validation
diff --git a/erpnext/accounts/doctype/sales_invoice/sales_invoice.py b/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
index a35c6b6..6be6a9b 100644
--- a/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
+++ b/erpnext/accounts/doctype/sales_invoice/sales_invoice.py
@@ -1954,9 +1954,9 @@
 		companies = [d.company for d in companies]
 		if company not in companies:
 			frappe.throw(
-				_("{0} not allowed to transact with {1}. Please change the Company.").format(
-					_(partytype), company
-				)
+				_(
+					"{0} not allowed to transact with {1}. Please change the Company or add the Company in the 'Allowed To Transact With'-Section in the Customer record."
+				).format(_(partytype), company)
 			)