Can't get to login.microsoftonline.com

I don't know if this is the right place for this question, I hope so. In short, for some reason I can't get to the website where I would login to my Office 365 account on my laptop.

This problem appears when using at least either Safari or Chrome, at my home network as well as my school wifi, so it shouldn't be browser or network specific. First the site loads for ages, and on Chrome the message "login.microsoftonline.com's server DNS address could not be found" appears. I noticed the problem over a week ago, and it just hasn't fixed itself and I have no idea how to do it. I've tried typing the address to the address bar, I've tried portal.office.com, I've tried using a Google link to get there, and even the link on my school's site. I've cleared all cache and cookies, reset all browser settings on both browsers, and yes, I've tried restarting the computer. And I know the problem isn't with Outlook or my account itself either, since I can access the website and the OWA-app on my iPhone.

I hope someone knows how to fix this.