Can someone please help? Safari error message driving me crazy

For the first time ever, when I insert the url address of one of my three wordpress websites, I am taken to my correct page: www.maxmagician.com but suddenly, out of nowhere, I get a Safari "drop down" box that appears "on top of my web site home page, and this drop down box shows the following error message:To view this page, you must log in to area “Dev” on devwp1.previewscreen.com:80 inside this error message box theire are two empty fiedls for me to fill ini: Name and Password beneath these blank fields si a small box to check off: Remember this password in my keychain. Then beneath this there is "cancel" or "login" buttons. I can bi-pass all this by NOT filing the balnk fields in (ie. with my Name and Password), and simply clicking on th e"login" button, then the Safari error message box "lifts up" and seems to vanish off of the screen, then a SECOND Safari error message box appears, saying the same thing as the previous one. Of I then, click on the "login button without filling in the blank fields, the Safari error message box vanishes and I am on my web site page, as I should be and all "looks" normal.

This is a new "bug" and it is driving me "crazy", as it keeps poping up whenever I want to cehck out my one site.

Anyone who can advise me on how to fix this problem will be condisred all knowing and all powerful. 🙂