[MM3-users] Chinese characters in list name shows question mark (?)

Hi list,

I set up a mailman3 server and built a few lists to test.

When I set the list name using Chinese characters, the web site shows correctly.  However in the subscribing welcome mail the list name was shown in question marks.  Screenshot is here:

https://nextcloud.slat.org/index.php/s/CxPjpYMbQzQ6444

The LANGUAGE_CODE settings.py (in Debian /etc/mailman3/mailman-web.py) is set to zh-tw , and USE_I18N and USE_L10N are all set to True.

Is there any other setting I should look at?

Thanks, Franklin