- Plesk for Linux
SNI support is disabled:
# grep SNI_SUPPORT /etc/psa/psa.conf
- Website is hosted on shared IP address.
- SSL support is enabled for website, but SSL Cerificates option is missing under Domains > example.com > Hosting Settings.
SNI support is not enabled.
Note: if you don't have administrative access to Plesk via SSH or RDP, contact your hosting provider regarding the issue