Can’t make recipient into type rich text, from AppleScript.

Hello. I have wrote the following code in Apple Script, where recipient is the recipient's name, email is the recipient's email address, body is the content of the email, and sub is the subject of the email.

However, Apple Script error reads 'Can’t make recipient into type rich text' and cannot recognize my recipient's email address. Can I get some help, thanking you in advance?

tell application "Microsoft Excel"

set recipient to value of column 1 of row 2 of sheet 1 of active workbook as text

set email to value of column 2 of row 2 of sheet 1 of active workbook as text

set body to value of column 3 of row 2 of sheet 1 of active workbook as text

set sub to value of column 4 of row 2 of sheet 1 of active workbook as text

end tell

tell application "Mail"

activate

set theMessage to make new outgoing message with properties {subject:sub, content:body, visible:true}

tell theMessage

make new to recipient at end of to recipients with properties {name:recipient, address:email}

end tell

actiate

end tell