fix: message for subscription when no current inv

erpnext/accounts/doctype/subscription/subscription.py

@@ -594,7 +594,7 @@ class Subscription(Document):
 		"""
 		current_invoice = self.get_current_invoice()
 		if not current_invoice:
-			frappe.throw(_("Current invoice {0} is missing").format(current_invoice.invoice))
+			frappe.throw(_("Subscription {0}: Current invoice is missing.").format(frappe.bold(self.name)))
 		else:
 			if not self.has_outstanding_invoice():
 				self.status = "Active"