If your model has no LCD monitor/If you are using TR4500 series or PRO-1000 series (Uppercase and lowercase letters are differentiated.) Multibyte characters cannot be used. You will get an error if the e -mail address you enter contains a character that cannot be used.
Error code B200 (or related errors B201 / B202 / B203 / B204 / B205 / B206 / B207) generally means that print head communication has failed and that your printer will require service or replacement.