Symptoms
grep SNI_SUPPORT /etc/psa/psa.conf
SNI_SUPPORT false- 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.
Cause
SNI support is not enabled.
Resolution
Note: if you don't have administrative access to Plesk via SSH, contact your hosting provider regarding the issue
1.Connect to the server using SSH.
2.Edit /etc/psa/psa.conf file and change SNI_SUPPORT value to true:
SNI_SUPPORT true
3.Restart psa service:
#service psa restart
4.Log into Plesk.
5.Reload server components under Tools & Settings > Server Components > Refresh.