Recently I have had problems with ELOG not accepting the certificates (in this case from https://letsencrypt.org/) probably due to the old version of the SSL library of the binary distribution for Windows.
I have tried to follow the instructions to set up ELOG to work with Apache but they are probably old.
I have a simple solution for the Apache installation of XAMPP, the example is for two separate logbooks using each its own ELOG service on the same server:

1. I have set up the two ELOG to run as http://my.server.example.com:8080/ and as http://my.server.example.com:8081/

2. in c:\xampp\apache\conf\httpd.conf I have enabled the following (I am not sure if all the modules are really needed but this works for me):

LoadModule proxy_module modules/mod_proxy.so
LoadModule proxy_http_module modules/mod_proxy_http.so
LoadModule headers_module modules/mod_headers.so
LoadModule proxy_html_module modules/mod_proxy_html.so
LoadModule xml2enc_module modules/mod_xml2enc.so

3. still in c:\xampp\apache\conf\httpd.conf, at the very end of the file I added the following:

ProxyRequests off

Redirect permanent /app1 https://my.server.example.com/app1/
ProxyPass /app1/ http://my.server.example.com:8080/
ProxyHTMLURLMap http://my.server.example.com:8080 /app1

Redirect permanent /app2 https://my.server.example.com/app2/
ProxyPass /app2/ http://my.server.example.com:8081/
ProxyHTMLURLMap http://my.server.example.com:8081 /app2

This way I can now connect to the two ELOG using https://my.server.example.com/app1/ and https://my.server.example.com/app2/ without troubles and no additional setting to either the configuration files of ELOG nor any need for virtual hosts, ...

I hope this might be of use.