Some other things I thought of while waiting for a response on this!
- Do you have HSTS enabled for this hostname? I ask because perhaps the HSTS entries in your browser could be fighting the new host. I believe there is a chrome:// flag you can access to delete individual entries so this might be worth trying to see if HTTPS begins working again at that point. <-- This is done in Chrome with chrome://net-internals/#hsts
- If you run a sudo service smartermail status in normal cases you'll see when we bind to port 80/443 logged, so you may be able to run that right after attempting HTTPS to see if any errors get logged when that happens.
- Does the new user you're running under have sudo privileges? Perhaps they're not able to stat the certificate directory and so we're running into an error there preventing the certificate loading? All of the PFX files in my test box show a user/group of root likely because this box was installed under defaults and with sudo being used.
Development says there isn't a single debug log that centers around PFX selection beyond our Certificates log file, but that this log file should show when we select the PFX from the directory along with any errors we encountered. The certificates log should contain some detail here at least:
16:34:35.187 ACME: Verification complete for host.name.com in system. Generating certificate
16:34:37.452 ACME: Certificate for host.name.com has been bound and will be used for future HTTPS connections.
16:34:37.457 ACME: Certificate for host.name.com has been bound and will be used for future HTTPS connections.
16:35:07.028 [10.1.5.164][21210258] SNI using fallback binding certificate host.name.com.pfx for (no hostname passed to SNI).
16:36:07.063 [10.1.5.164][28265781] SNI using fallback binding certificate host.name.com.pfx for (no hostname passed to SNI).
Based on the code that leads into this area though the biggest possible culprits are the certificates path directory and/or the password being used to access those files. You've already checked there though so I think your best bet might be a support ticket so we can collect some examples and have that team do a review for us.
Kyle Kerst
Lead Internal Network/System Administrator
SmarterTools Inc.