Answering this thread specifically(?) using email cant be done, It give this error:
We’re sorry, but your email message to [“email@example.com”] (titled Re: [Whonix Forum] [Website] Long Wiki Edits Thread) didn’t work.
We only accept replies to original notifications for 90 days. Please visit the topic to continue the conversation.
Is there a way to extend replies time? (maybe even infinite?)
We’re sorry, but your email message to [“firstname.lastname@example.org”] (titled Re: [Whonix Forum] [Support] Torbrowser not starting) didn’t work. We only accept replies to original notifications for 90 days. Please visit the topic to continue the conversation.
Discourse has a log on processed e-mails built-in. Not sure this is included. Searching by time doesn’t work but but I could look at the e-mail address it was sent to. Could you please post the first 4 random strings or the e-mail you replied to?
In Thunderbird when using multiple e-mail addresses, one has to send from the e-mail address used to sign up for the discourse forum. But in the e-mail Write button (e-mail draft window) choosing using From: does not mean much. It’s just a textual string. It doesn’t mean that the corresponding SMTP server will be used. For example if someone had both, a microsoft e-mail address and a google mail address, setting From: to the microsoft e-mail address doesn’t mean that the microsoft SMTP server would be used for outgoing e-mail.
Under Thunderbird -> Edit -> Account settings -> Outgoing Server (SMTP) the default server might be used. Could be settings issue or Thunderbird bug.
I recommend against using multiple SMTP servers in Thunderbird. These are easily confused through settings or bug from one to another.
To avoid issues for replying to a forum thread by e-mail:
If using Thunderbird, do not use the Reply button. Use the Reply All button, if available.
Whatever button used: make sure reply is to discoursereplies+6e5f0f[redacted]@whonix.org (which has a chance of working) and not to email@example.com which is guaranteed to fail.