I thought bbc is another email provider. Hehe. It is just Blind Carbon Copy
Okay try this, open your Wordpad > then copy all email addresses there by holding CTRL key then tap A key> once highlighted > go to the bbc section of your compose email then hold CTRL key then tap V key
If it doesn't work, try to copy and paste first all the email address from your Wordpad to Notepad, if all are copied in your Notepad, then copy and paste it now to the bbc section of your email