Are you sure that you did really registered your own skype account? So base on the error message, your account which is Microsoft account can't be found.
Why not just create a new one? Build another Microsoft account since it's new, so I think you don't have that much contacts there.
Since there is nothing to lose for creating a new one.
It is a very new account and i dont have any contact on it but creating a new brings more issue because the previous email used to register the account have been recorded on their database and they confirmed it when i tried to create another account with it but to register they say another thing.
I'm sure you're using their app but did you try to login using browser only? I encountered this issue before and I only try so many times on their app, browsers and even on their android app before I can login.
Online chats web.skype says the same thing, very confusing.