MFC-L2720DW FAQs & Troubleshooting MFC-L2720DW Not your product? Sort by: Updated Date Popularity 2 Results 1. 05/11/2015 When I send a fax from the machine, an error "not register." or "not registered." is displayed. 2. 05/11/2015 I am experiencing problems sending a fax. Fax FAQs & Troubleshooting