Thanks @rg305 that helps.
I made it until this far.
So far I made these changes in my ssl.conf,
<VirtualHost :80>
RewriteEngine On
RewriteCond %{HTTPS} off
RewriteRule (.) https://mec-staging2.longiviti.com$1 [R,L]
<VirtualHost *:443>
…
SSLCertificateFile /etc/letsencrypt/live/mec-staging2.longiviti.com/cert.pem
SSLCertificateKeyFile /etc/letsencrypt/live/mec-staging2.longiviti.com/privkey.pem
SSLCertificateChainFile /etc/letsencrypt/live/mec-staging2.longiviti.com/fullchain.pem
…
ProxyRequests Off
<Proxy *>
Order deny,allow
Allow from all
ProxyPass “/” “ajp://mec-staging2.longiviti.com:8009/” retry=0 timeout=5
ProxyPassReverse “/” “ajp://mec-staging2.longiviti.com:8009/”
…
</ VirtualHost>
But I’m still confused what’s missing from my configuration.