Understanding how multi-store should be configured

I am in the middle of setting up a multi-store environment.  The current problem is store 1 works as intended including its SSL certificate, but the SSL certificate for store 2 is not kicking in, so store 2 is showing "Not secure" in Google Chrome and other browsers.  Store 2 does work, if you bypass the browser security warning (but we all know customers aren't going to do that).  Relevant details are below.  I apologize, I was caught off guard by the entire multi-store process and ended up trying to solve this problem myself when I thought I would have help.  I would never have attempted this on my own, but here I am...  I don't have a good knowledge of what I'm doing, and I've read through as many forum entries and documentation as I can about multi-store, but the material is vague, especially for someone like me who needs to learn more about how DNS, servers, IIS, multi-store, and SSL all work together.   I would appreciate help with troubleshooting - how can I fix this so the SSL works for both sites?  Thank you!

Nop Commerce v4.6
Store records -
  Store Name:  Store 1
  Store URL:  https://www.store1.com/
  SSL:  Enabled
  Host values:  store1.com,www.store1.com
  Display order:  1

  Store Name:  Store 2
  Store URL:  https://www.store2.com/
  SSL:  Enabled
  Host values:  store2.com,www.store2.com
  Display order:  2

Registrar:  
  NAMESERVER records set up for store1.com and store2.com to point to our ISP/server
  FORWARDING set up for store1.net and store1plus.com to go to store1.com
  FORWARDING set up for store2.net to go to store2.com

ISP/Server - 2 sites hosted, store1.com and store2.com
  store1.com  Domain
    A record: store1.com  11.11.11.70 (store 1 IP)
    A record: www.store1.com  11.11.11.70 (store 1 IP)
  store1.net  Domain pointer but not configured
  store1plus.com  Domain pointer but not configured
  store2.com  Domain
    A record: store2.com  11.11.11.70 (store 1 IP)
    A record: www.store2.com  11.11.11.70 (store 1 IP)
  store2.net  Domain pointer
    A record: store2.net  11.11.11.127 (store 2 IP)
    A record: www.store2.com  11.11.11.127 (store 2 IP)

SSL:  Set up and established for both store1.com and store2.com (regular SSL certificates, not multi domain SSL, nor wildcard SSL)  store1.com is working, store2.com is not

I resolved this by purchasing a multi-domain "UCC" SSL certificate for the main store and adding all relevant URLs to that certificate.  My domain registrar kindly refunded the unused amount for my two regular SSL certificates when I purchased the multi-domain, which was one of my concerns about jumping to the multi-domain certificate.  This question can be closed - it is resolved.