Error 3219 on Windows Live Mail

Since 10th Aug I have been getting Error 3219 on my Hotmail.co.uk account (can't send or receive) on my laptop (Windows 10) and PC (Windows 7), both using Windows Live Mail.

I can still use my Hotmail.com account on both setups.

I know WLM is being phased out (very sadly ...) but why the error with one account and not the other? Can I get the Hotmail.co.uk account working again on WLM and how?

Both accounts are working on my laptop (Windows 10 and using Windows Mail - without the ease and clarity of WLM!).

If getting my hotmail.co.uk account (and potentially, soon, my hotmail.com account) on my PC running Windows 7 proves no longer possible then what e-mail software can I use on Windows 7 to replace WLM?

It seems as if an automatic 'upgrade' that Microsoft initiated about the 10th Aug. has, in fact, successfully "downgraded" what I can do with both my laptop and PC ...

Any help/advice appreciated!

Thanks.