Rated 4 out of 5 stars

To my great regret, my add-on is not working. I get this error: "Sending of the message failed.
An error occurred while sending mail. The mail server responded: Error: transaction failed, blame it on the weather: backend: invalid email address: not owned by user. Please check the message and try again.".

I should point out that I am using Proton Mail Bridge running macOS 12.5 on a mac-mini Intel.
Thunderbird 102.1.0

The built-in redirect works without problems, but I can't use it because it's not available in Message Filters.

Let me explain the situation. I have a custom domain connected in protonmail and with emails for my whole family. I want to use filters to automatically redirect emails to my family members personal emails.

upd.
2Günter
1. I understand the difference :)
2. Apparently, it's the provider's problem, not the add-on.
3. v1.23

I tried running the same scenario under Ubuntu, nothing changed. But I found a solution without redirecting messages, so my problem is solved.

The add-on is very useful and needed. Due to the fact that I could not try the add-on at work, only four stars, sorry.

This review is for a previous version of the add-on (1.23). 

1. Be sure you're really using the add-on. It's called by the 'Redirect' with the icon in front of it far down in the context menu of a mail. The 'Redirect' below the 'Forward' entries calls the TB internal redirect function which works quite differently.

2. Not all providers accept mails if the from address is not from their own domain (e.g. outlook and the german providers web.de and gmx.de). But this is the normal case when using the add-on. Seems that Proton belongs to these providers as the error 'invalid email address: not owned by user' suggests.

If you have access to another SMTP mail server, try that server to redirect the mail (change the 'From' in the first line of the add-ons popup window).

3. Redirecting using this add-on via filters is supported since version 1.21 of the add-on