On the IIS 7 sometime you would find the SSL binding for the website has been deleted and not replaced, or has been deleted and replaced with invalid certificate info. The problem occurs because of a legacy SSL certificate hash property interfering with the current SSL binding, resulting in the correct binding being deleted.
And sometime following entry is logged in the event viewer
Log Name: System Source: Microsoft-Windows-HttpEvent Date: 3/31/2010 2:43:28 PM Event ID: 15300 Task Category: None Level: Warning Keywords: Classic User: N/A Computer: IISServer Description: SSL Certificate Settings deleted for Port : x.x.x.x:443
For the Fix
Read KB article 2025598