- Plesk for Windows
How to enable SSI support?
1. Go to Home > Tools&Settings > Add/Remove Components > Plesk Hosting Features and make sure that Server Side Includes component is installed. Install if it is not.
2. Go to Plesk > Domains > example.com > Hosting Settings and tick SSI support checkbox in Web Scripting and Statistics section
Also, it can be enabled via command line
C:\> plesk bin site.exe --update example.com -ssi true