On page ID 136 you load module "Easy Vimeo Videos" few times and this is your source of SSL problems, otherwise SLL problem would be all on SPPB pages, right.
When I disabled Module addon that load "Easy Videmo Videos" module - problem gone.
My Advice: update that module to v4.2 or contact with module developer. Becuase on module website in changelog I found that:

and you have v4.0 installed with "certificate problem".
Don't worry, everything can be fixed, if was broken. And I, as you can see, have to take on the role of Sherlock Holmes from time to time ;)