Can't log into Microsoft Account

Hey! I just bought Minecraft and I can't seem to login to my Microsoft account. The login window appears for two seconds and disappears immediately. I cannot join any server or anything. This is very bad on your side and if I didn't know better I'd try and give a 1 star review on your product. I bought a key from amazon and the key works, but I just can't log in. Also this is my birthday gift and it'd be very kind if you could get it to work. Thanks! Here's a screenshot: