login failed

Hi,

Everytime I add or update a page, it brings me to a blank page with in the upper left corner “login failed”, instead of coming back to the editing page with the header “page updated”.
It still saves the changes I made, but I’d like to be able to come back to the editing page. Does anyone know how to do that?

I thought this change happend after installing a plugin that allowed me to control the autosave, revison and other stuff options, but even after deactivating it and deleting it, it doesn’t work.