If, like me, you are getting Interfolio requests from students on the job market, you may be aware that Interfoliio is having some technical issue, where the "upload" link doesn't work.  In some cases, I asked the student to resent the request, and it worked.  But even simpler was forwarding the request to myself–the link in the forwarded version worked!  (Interfolio Help recommended this.) I hope that helps some others out there!