Upload Plugin from.zip returning 404

I updated to 5.02 and everything has worked fine. I’ve needed to update a couple of plugins and one of them I need to install through the upload plugin. Everything runs through as expected but when it is at 100% it returns a 404 page. I’ve tried with various different plugins and all doing the same. Any ideas what the issue could be?

The page I need help with: [log in to see the link]