we had this same issue starting this morning and goti it solved... hope this helps...
SSL on IIS 8
Everything was working fine yesterday and last night our SSL was updated on the IIS site.
While checking out the site Bindings to the SSL noticed that IIS8 has a new checkbox Require Server Name Indication, it was not checked so preceded to enable it.
That triggered the problem.
Went back to IIS, disabled the checkbox.... Problem Solved!!!!