Hey there. Did you also try a different machine? Can others access it? Can you successfully view other links (not protected with a password)?
Can you try creating such a link yourself, with a password, and try accessing it? Also - try opening it through an incognito / privacy tab.
Sometimes there are DNS issues and other connection / network problems that resolve on their own or happen randomly due to some maintenance, but are hard to track. You can open up developer tools on your browser (Ctrl+Shift+I), go to the Network tab, then open the link and see if there any errors thrown.