MFC-L3770CDW FAQs & Troubleshooting MFC-L3770CDW Not your product? Sort by: Updated Date Popularity 1 Results 1. 04/07/2023 The scanned data is attached to an E-mail application which I do not use regularly, or the error message indicating no default E-mail application is registered on my computer (CC4-121-[error code]) when trying to scan a document directly into my E-mail application using ControlCenter4 or the SCAN key on my Brother machine. Scan FAQs & Troubleshooting