See F-Status here: https://sritest.io/#report/b3bf2db1-ac81-44ed-9d42-41f963b86d9e
Certificate issues:
You have 1 error
Certificates installed in the wrong order.
Some certificates in the chain are installed in the wrong order. See details below. Reinstall the certificates in the proper order.
Warnings
Root installed on the server.
For best practices, remove the self-signed root from the server.
F-I-A-A+ X-status: https://observatory.mozilla.org/analyze.html?host=hofstadmavohavo.nl
WARNING: Name servers software versions are exposed: http://www.dnsinspect.com/hofstadmavohavo.nl/1483052003
exploitable.
polonus