How configure multiples process on 443 port? Apache - ubuntu - node.js

Question

here its my problem:
I have 2 applications configured on a server. React (client) and nodejs backend with their respective domains.
1 - example1.com
2 - example2.com
I have configured both SSL certificates for each of it as well. The problem occurs when you want to start the backend on the same port that the client is running.
Is it possible to run 2 processes on it? How should I do it?
these are my virtual host files:
example1-le.ssl.conf
<IfModule mod_ssl.c>
<VirtualHost *:443>
ServerName example1.com
ServerAlias www.example1.com
ServerAdmin info#xample.com
DocumentRoot /var/www/example1
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined
SSLCertificateFile /etc/letsencrypt/live/example1.com/fullchain.pem
SSLCertificateKeyFile /etc/letsencrypt/live/example2.com/privkey.pem
Include /etc/letsencrypt/options-ssl-apache.conf
</VirtualHost>
</IfModule>
example1.conf
ServerName example1.com
ServerAlias example1.com
ServerAdmin info#example.com.ar
DocumentRoot /var/www/example/build
<Directory "/var/www/example/build">
RewriteEngine on
# Don't rewrite files or directories
RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
# Rewrite everything else to index.html to allow html5 state links
RewriteRule ^ index.html [L]
</Directory>
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined
RewriteCond %{SERVER_NAME} =example1.com
RewriteRule ^ https://%{SERVER_NAME}%{REQUEST_URI} [END,NE,R=permanent]
</VirtualHost>
And the same for the another one.
When i tried to start the second project i receive : EADDRINUSE: address already in use :::443
Thanks a lot for you help

Answer 1

You can NOT have to 2 different processes bind on the same port. What Olaf Kock suggested works fine and is easy to implement: you install apache on a dedicated server (or on the same machine: there's no difference) and then you configure a reverse proxy (the module is called mod_proxy). There are also other solutions (like haproxy) which require a bit more complex configuration but provide many more configuration options.