Until about one month ago, I had mailman3 and mailman3-web successfully running on Debian 12. However, when I access any page such as https://example.com/mailman3/postorius/lists/ now, I just get a 500 server error.

/var/log/mailman3/web/mailman-web.log logs this at every request: invalid request block size: 14056 (max 4096)...skip

I read somewhere that adding buffer-size = 65536 to uwsgi.ini might help. It indeed makes a difference, but unfortunately I just get another error instead: [pid: 4067215|app: -1|req: -1/1] () {256 vars in 14055 bytes} [Tue Jan 28 18:06:30 2025] => generated 0 bytes in 0 msecs ( 500) 0 headers in 0 bytes (1 switches on core 0)

There are no other errors in the logs.

I proxy mailman in Apache like this:

Alias /mailman3/favicon.ico /var/lib/mailman3/web/static/postorius/img/favicon.ico Alias /mailman3/static /var/lib/mailman3/web/static

<Directory "/var/lib/mailman3/web/static"> Require all granted </Directory>

<IfModule mod_proxy_uwsgi.c> ProxyPass /mailman3/favicon.ico ! ProxyPass /mailman3/static ! ProxyPass /mailman3 unix:/run/mailman3-web/uwsgi.sock|uwsgi://localhost-mailman3/ </IfModule>

and mailman3's uwsgi.ini looks like this: [uwsgi] uwsgi-socket = /run/mailman3-web/uwsgi.sock enable-threads = true chdir = /usr/share/mailman3-web wsgi-file = wsgi.py master = true process = 2 threads = 2 uid = www-data gid = www-data env = HOME=/tmp plugins = python3 attach-daemon = python3 manage.py qcluster logto = /var/log/mailman3/web/mailman-web.log buffer-size = 65536

Any idea what could be wrong or how to debug this further?

I'm using mailman3-full 3.3.8-2~deb12u2 and mailman3-web 0+20240312-1 packages.