Hello All,
Thanks to Osiris & Danb35 for helping me yesterday.
I faced few issues to install and configure the certificate using ACME. Mostly it was External DNS, Port Forwarding on the router & Firewall settings. I was able to fix all of them and successfully finished acquiring SSL certificate and installed it for Exchange Server 2019.
I made note of all the fixes and created a detailed document that might be useful for others, if they plan to use this certificate for Exchange Server. The document will work for Exchange Server 2013, 2016 & 2019. Here is the link to the document
Enjoy!
Ram