Hi Zhang,

Yes, that line is already active in 00-default-ssl.conf.  It has both listen 443 ssl; and listen [::]:443 ssl;  The problem I have is that when I type : nginx -V it responds with what is below:
Prior to the upgrade it used to have --with-ipv6

As you can see that has now gone, so I need to make that active again, but don't know how to add the --with-ipv6 back to the nginx configuration.

Thanks a lot,
Stephen

nginx version: nginx/1.14.0 (Ubuntu)
built with OpenSSL 1.1.1  11 Sep 2018
TLS SNI support enabled
configure arguments: --with-cc-opt='-g -O2 -fdebug-prefix-map=/build/nginx-GkiujU/nginx-1.14.0=. -fstack-protector-strong -Wformat -Werror=format-security -fPIC -Wdate-time -D_FORTIFY_SOURCE=2' --with-ld-opt='-Wl,-Bsymbolic-functions -Wl,-z,relro -Wl,-z,now -fPIC' --prefix=/usr/share/nginx --conf-path=/etc/nginx/nginx.conf --http-log-path=/var/log/nginx/access.log --error-log-path=/var/log/nginx/error.log --lock-path=/var/lock/nginx.lock --pid-path=/run/nginx.pid --modules-path=/usr/lib/nginx/modules --http-client-body-temp-path=/var/lib/nginx/body --http-fastcgi-temp-path=/var/lib/nginx/fastcgi --http-proxy-temp-path=/var/lib/nginx/proxy --http-scgi-temp-path=/var/lib/nginx/scgi --http-uwsgi-temp-path=/var/lib/nginx/uwsgi --with-debug --with-pcre-jit --with-http_ssl_module --with-http_stub_status_module --with-http_realip_module --with-http_auth_request_module --with-http_v2_module --with-http_dav_module --with-http_slice_module --with-threads --with-http_addition_module --with-http_geoip_module=dynamic --with-http_gunzip_module --with-http_gzip_static_module --with-http_image_filter_module=dynamic --with-http_sub_module --with-http_xslt_module=dynamic --with-stream=dynamic --with-stream_ssl_module --with-stream_ssl_preread_module --with-mail=dynamic --with-mail_ssl_module --add-dynamic-module=/build/nginx-GkiujU/nginx-1.14.0/debian/modules/http-auth-pam --add-dynamic-module=/build/nginx-GkiujU/nginx-1.14.0/debian/modules/http-dav-ext --add-dynamic-module=/build/nginx-GkiujU/nginx-1.14.0/debian/modules/http-echo --add-dynamic-module=/build/nginx-GkiujU/nginx-1.14.0/debian/modules/http-upstream-fair --add-dynamic-module=/build/nginx-GkiujU/nginx-1.14.0/debian/modules/http-subs-filter

I didn't a quick test, "nginx -V" doesn't print "--with-ipv6", but it still supports IPv6.

When you run "netstat -ntlp", does it show you IPv6 port :::80 and :::443?

With iRedMail Easy, Nginx is configured to handle the /.well-known/ directory with directory /opt/www/well_known/. Does your certbot config file updated to use this directory?

Please show us full content of file /etc/letsencrypt/renewal/mail.domain.co.nz.conf.  Note: please hide sensitive info before pasting.