Linked hotmail accounts not working

All of a sudden this week I can't sign into my linked account which is very important I can access both as husband has cancer and messages go to the one I use for business like purposes.

I went through the steps to relink accounts and it says this page is no longer available!

At the moment I have sign in and out of both accounts which when you're in a hurry is very time consuming.

Are you able to explain why this  has suddenly happened?

Thank you