Had this error and read the multiple threads on solution for hotmail account.  Delete account, wait a while and reinstall the HM account.

I did this and I no longer have the error message. BUT, window live mail will no longer sync with the hotmail account.  I have several email accounts, comcast, gmail and hotmail. They all work fine except Hotmail.  Again, the error message is gone, is says it's checking, but I have had no new HM messages since september 9. 

I am using the W10 built in mail to check HM, but I really don't like the layout.