My VM setup:
Azure VM: Windows server 2019 datacenter IIS 10
I have purchased a domain & Standard SSL from GoDaddy and pointed it to the Azure VM. Initially, the website was running on IIS using HTTP on port 80. I have purchased SSL from godaddy and installed them as the following reference https://in.godaddy.com/help/manually-install-an-ssl-certificate-on-my-iis-10-server-27349
Then I tried to bind the certificate with my website using https on port 443, where newly installed SSL certificate name not showing in add site binding window of the website in SSL Certificate dropdown
The common reason behind the issue is when the imported certificate doe s not have a private key associated with it or its broken because of some reason.
to resolve the issue you could try to import the .CER file to your system(from where the certificate is requested) personal store and export it with a private key. Then copy the .pfx file to the required server and import it from the server certificate option under IIS. This would fix the issue.
refer this below link for more detail:
https://serverfault.com/questions/469987/ssl-certificate-not-found-in-the-drop-down-list-iis-7