Preview large pdf files shows 1 page only

My Memphis docs plugin was working fine. Recently when adding a pdf file over 1mb the preview function displays the first page only. I can download the file and verify that the entire file was uploaded. On smaller files it works fine. I have documents that I added a couple of weeks ago that are 20 pages and 4mb, and they still preview OK.
I have tried the suggestion with the third-party settings in every combination, with no luck. I tried setting up the box preview, received and setup a key. When I try it I get a error 404. Has anyone experienced this and found a solution.