I don’t know CloudPanel, but the error messages seem to be self-explanatory:
'if ENV["DISCOURSE_SMTP_ADDRESS"] == "smtp.example.com"; puts "Aborting! Mail is not configured!"; exit 1; end'
'if ENV[\"DISCOURSE_SMTP_ADDRESS\"] == \"smtp.example.com\"; puts \"Aborting! Mail is not configured!\"; exit 1; end'"
It looks like your email wasn’t configured during ./discourse-setup or inside app.yml (you can edit it manually at any time). 