小PDF文件上传到wordpress的http错误

I've been trying to resolve an issue we're having with a wordpress site and the host (godaddy) is being less than helpful as they can't recreate the problem on their side. One of the other admins on the site asked if I could look into why he couldn't upload a pdf file (only 212k)

I've tried all the obvious things, different files including .png adding the up memory limit code to the config file deactivating the theme and plugin files and nothing is working. I can still upload .jpg files though

The baffling thing is godaddy support tried uploading a file and said it worked fine. I've tried uploading the same pdf file to another site i'm admin on and it worked first time, also the other admin is based in another town from me so I know it's nothing to do with my connection or the file? really stumped on this one