I just updated to the latest WP version, updated all plugins as well and to this message for my blog at http://www.balboaexplorer.com/blog
"The server http://www.balboaexplorer.com at WP-Files requires a
username and password.
Warning: This server is requesting that your username and password be sent in an insecure manner (basic authentication without a secure connection)."
I - any visitor - have to cancel several times before I can get into the site but no images included in posts are shown.
The weird thing is: there is no WP-Files directory. I didn't touch any settings.
The initial problem I had was that I could not add any image to a post; clicking on the 'add image' would not have any window pop up'. That's why I tried an upgrade first. Now it's even worse.