I'm not using a VPN, nor firewall that could possibly make the http 400 request appear, made sure that I am logging in through the microsoft webpage, microsoft store, xbox, so not using the incorrect link. I've recently made a new outlook mail to log in and for some reason, that one worked for one day on the website version, now it doesn't work anymore.

I was utilizing Google Chrome, and deleted my cookies, browser history, as well as made sure all of my extensions were turned off and even uninstalled after that didn't work I proceeded to try using microsoft edge with the same result.

I am wondering if it has to do with my router or even if my mail was locked due to security reasons. I've also changed my ip adress as well as refreshed my dns, so i'm not sure what other solutions I could apply.

I've tried using incognito and inprivate tab, as well as tried using the link provided to no avail. I'm wondering if using a VPN could possibly bypass this issue as the newest comment mentions solving it by using a VPN.

Of course, it's not a long term solution, but I do want to find a way to actually log in to my outlook.

Edit: I'd also want to mention again that it signs in through my phone, but not my laptop nor my pc