I have been using Windows Live Mail on Windows 10 on my Lenovo PC without any problems until a few days ago when I started getting a dialogue box pop up saying "To help protect your online id account you must sign in again".

If I select "OK" I am taken to the sign in screen where I enter my email address & password and that gives me the same dialogue box asking me to sign in again. This loop continues, presumably for as long as I am prepared to keep entering my details.

This does not affect my email log in and emails are sent & received as usual, so there is limited impact, but my contacts have disappeared - presumably because WLM is not able to sign in and sync them. They are still visible on my other PCs which are not having this issue.  

I have made no recent changes to my PC but there was a series of Quality Updates from Microsoft a few days ago. I'm not sure if this started then but I suspect it did.

Can anyone help please?