404 page not found error when attaching file or inserting video or image

Topics: ASP.NET 2.0
Dec 8, 2015 at 1:42 PM
Edited Dec 8, 2015 at 1:43 PM
I am (still) using version 2.5

When I attach a file or insert a video or image then the file I point to is being uploaded. After upload reaches 100% the page seems to be reloaded, but this time with a 404 error -file or directory not found.

The address bar in my browser (Chrome) still reflects the url it had when I started adding the page. Reloading that url by putting the cursor in the addrss bar and pressing enter shows an empty page form.

Any idea what could cause this?