Thanks for reporting your issue. I see in the bnsupport bundle you used the bncert-tool, and this tool renames the
bnconfig tool. Can you try running the next command on your server to disable the banner?
sudo /opt/bitnami/apps/discourse/bnconfig.disabled --disable_banner 1
After that, restart Apache for changes to take effect
sudo /opt/bitnami/ctlscript.sh restart apache
Regarding configuring the SMTP settings for Discourse, you can get more information in the next guide. Note that for sending emails it should not be necessary to open SMTP related ports.