I am starting to agree this is some sort of certificate issue.
I found this post (the entire thread looks to have issues similiar to ours that resulted in delayed certificate updates on SmartThings, which eventually resolved themselves).
From that post I went off and setup an apigee.com account for free. I then changed all the urls and have them running through apigee.com, and it all is working now. I don’t think this is an ideal solution as apigee can see your username and password, but it does confirm the api still works correctly and it is either SmartThings having SSL issues with the simplisafe api or simplisafe blocking smartthings.