Rated 2 out of 5 stars

Sadly I run with latest Thunderbird / just installed addon into same problem as b4c89e: " Transaction failed Unauthorized sender address."
It seems that your addon let decide which email should be used to sent the "redireted" email but send the email with origin email addres... this was working withe the original mail redirct addon

This review is for a previous version of the add-on (1.33). 

"Unauthorized sender address" and similar errors are not a problem of the add-on, it's a problem of the provider you are using to resent the mail. They simply does not allow a sender address which is not from their own domain.
The only workaround is to use another mailprovider which allows arbitrary sender addresses.