无法获取本地邮件。使用Apple脚本的应用程序帐户

我正试图通过邮件中的id获取消息。应用程序使用Apple脚本。如果邮件仍在收件箱中,它可以工作,但是我在本地mac电脑上有帐户名为“on my mac”的邮件,每当我运行此脚本时,它会给我一个错误“Mail got a error:Cant get account”on my mac。号码:-1728。

# THIS WORKS
# set MessageID to 375586
# set _mailBox to "INBOX"
# set _account to "TheWilliamson"

# THIS DOESN'T WORK
set MessageID to 11351
set _mailBox to "2001"
set _account to "On My Mac"


tell application "Mail"

    try
        set mybox to mailbox _mailBox of account _account

        # ERROR: Mail got an error: Can’t get account "On My Mac". Number: -1728

    on error eStr number eNum
        display dialog eStr & " Number: " & eNum buttons {"OK"} default button 1
        return
    end try
end tell