diff -rupN electronic_invoice_dian/models/account_move.py electronic_invoice_dian.patch/models/account_move.py
--- electronic_invoice_dian/models/account_move.py	2021-07-01 17:18:28.506355243 -0500
+++ electronic_invoice_dian.patch/models/account_move.py	2021-08-18 00:05:11.094308447 -0500
@@ -642,7 +642,7 @@ class AccountMove(models.Model):
                 continue
             email_pool = email_pool + email
             invoice.create_transaction_log(invoice, 'email_sent', 'OK')
-            invoice.ei_email_sent = True
+            invoice.sudo().ei_email_sent = True
         if force_send:
             email_pool.send()