Changed Permalinks, Now website asks me to login and images are gone.

So, I am working on a website that is not open yet:

https://seizethebeat.net/website

and I wanted to change the Permalinks. So, I did, but I realized that it would break all the page links and things I had set up, so I changed it back to the default.

Well then my logo disappeared and shows a blue box with a “?” in it, and it also does this for several other images on the website. Also, Whenever I try to upload a new logo or go to any page a box pops up and says:

To view this page, you must log in to area “WP-Files” on seizethebeat.net

Or something to that extent. I tried all my usernames and passwords I have setup and they won’t work. I heard that this sometimes means you were hacking, but I doubt anyone is trying to hack me, and it was right away the permalink changes. Can anyone help?