==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): .9
- Deployed with iRedMail Easy or the downloadable installer? Installer
- Linux/BSD distribution name and version: ubuntu linux 18.10
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): MySQL
- Web server (Apache or Nginx): NGINX
- Manage mail accounts with iRedAdmin-Pro? No
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

I recently updated an expired certificate.  As soon as the old cert expired all IMAP clients ceased connecting.  Third party SSL checkers say the new certificate is correct but no IMAP client connections succeed.  The NGINX log yields the following message:

conflicting server name "_" on 0.0.0.0:443, ignored

Please help!!