Cannot send to email address having accented characters in the mailbox name
Using the currently-latest version of Thunderbird (91.3.2 (64-bit)), I need to send to an email address belonging to the French government in which the mailbox portion contains an E with an acute diacritical mark (é). When I get Send, it pops up a window telling me it's sending, then that window disappears. That's it. No error indication. Nothing added to the Sent folder. I tried a different SMTP server, same result. I have a catch-all email address, so I tried sending to myself (tést@...) and got the same results. I was able to use one of those SMTP servers, through their web portal, to successfully send to that address, and received it on the other email server, which proves that at least one of those SMTP servers doesn't mind accents in email addresses.
I read blogs on how to enable logging in Thunderbird, and after doing so, tried sending to that same address and a good address. The log file got created but nothing was logged (not even for the one that succeeded).
So, it appears that there's a bug in Thunderbird, where it should at least display an error message, although no error should have been returned from one of those SMTP servers. Functional logging would be nice as well.