From an Authors Alliance Blog Post:
As feared, it now appears that SSRN is taking up restrictive and hostile positions against authors’ ability to decide when and how to share their work. Reports are surfacing that, without notice, SSRN is removing author-posted documents following SSRN’s own, opaque determination that the author must have transferred copyright, the publisher had not consented to the posting, or where the author has opted to use a non-commercial Creative Commons license. One author, Andrew Selbst, reported that SSRN refused his post even though the article’s credits reflected his retained copyright.
It is also important to remember that your work does not need to be restricted to any one venue. Try SocArXiv, but also see if you can host your work in an institutional repository or on a personal website. Make your work available wherever it can best reach your readers. It is also worth protesting the practices that would restrict your work’s availability and reach by leaving the services adopting them. If the reports about SSRN’s new practices are accurate, then it may be time to leave SSRN and adopt more author-friendly alternatives.
Read the Complete Blog Post
SSRN also tweeted an item on July 15, 2016.